A Life Cycle Assessment Case Study of Coal-Fired Electricity Generation with Humidity Swing Direct Air Capture of CO2 versus MEA-Based Postcombustion Capture.

PubMed

van der Giesen, Coen; Meinrenken, Christoph J; Kleijn, René; Sprecher, Benjamin; Lackner, Klaus S; Kramer, Gert Jan

2017-01-17

Most carbon capture and storage (CCS) envisions capturing CO 2 from flue gas. Direct air capture (DAC) of CO 2 has hitherto been deemed unviable because of the higher energy associated with capture at low atmospheric concentrations. We present a Life Cycle Assessment of coal-fired electricity generation that compares monoethanolamine (MEA)-based postcombustion capture (PCC) of CO 2 with distributed, humidity-swing-based direct air capture (HS-DAC). Given suitable temperature, humidity, wind, and water availability, HS-DAC can be largely passive. Comparing energy requirements of HS-DAC and MEA-PCC, we find that the parasitic load of HS-DAC is less than twice that of MEA-PCC (60-72 kJ/mol versus 33-46 kJ/mol, respectively). We also compare other environmental impacts as a function of net greenhouse gas (GHG) mitigation: To achieve the same 73% mitigation as MEA-PCC, HS-DAC would increase nine other environmental impacts by on average 38%, whereas MEA-PCC would increase them by 31%. Powering distributed HS-DAC with photovoltaics (instead of coal) while including recapture of all background GHG, reduces this increase to 18%, hypothetically enabling coal-based electricity with net-zero life-cycle GHG. We conclude that, in suitable geographies, HS-DAC can complement MEA-PCC to enable CO 2 capture independent of time and location of emissions and recapture background GHG from fossil-based electricity beyond flue stack emissions.

PBP5, PBP6 and DacD play different roles in intrinsic β-lactam resistance of Escherichia coli.

PubMed

Sarkar, Sujoy Kumar; Dutta, Mouparna; Chowdhury, Chiranjit; Kumar, Akash; Ghosh, Anindya S

2011-09-01

Escherichia coli PBP5, PBP6 and DacD, encoded by dacA, dacC and dacD, respectively, share substantial amino acid identity and together constitute ~50 % of the total penicillin-binding proteins of E. coli. PBP5 helps maintain intrinsic β-lactam resistance within the cell. To test if PBP6 and DacD play simlar roles, we deleted dacC and dacD individually, and dacC in combination with dacA, from E. coli 2443 and compared β-lactam sensitivity of the mutants and the parent strain. β-Lactam resistance was complemented by wild-type, but not dd-carboxypeptidase-deficient PBP5, confirming that enzymic activity of PBP5 is essential for β-lactam resistance. Deletion of dacC and expression of PBP6 during exponential or stationary phase did not alter β-lactam resistance of a dacA mutant. Expression of DacD during mid-exponential phase partially restored β-lactam resistance of the dacA mutant. Therefore, PBP5 dd-carboxypeptidase activity is essential for intrinsic β-lactam resistance of E. coli and DacD can partially compensate for PBP5 in this capacity, whereas PBP6 cannot.

Preface: SciDAC 2008

NASA Astrophysics Data System (ADS)

Stevens, Rick

2008-07-01

The fourth annual Scientific Discovery through Advanced Computing (SciDAC) Conference was held June 13-18, 2008, in Seattle, Washington. The SciDAC conference series is the premier communitywide venue for presentation of results from the DOE Office of Science's interdisciplinary computational science program. Started in 2001 and renewed in 2006, the DOE SciDAC program is the country's - and arguably the world's - most significant interdisciplinary research program supporting the development of advanced scientific computing methods and their application to fundamental and applied areas of science. SciDAC supports computational science across many disciplines, including astrophysics, biology, chemistry, fusion sciences, and nuclear physics. Moreover, the program actively encourages the creation of long-term partnerships among scientists focused on challenging problems and computer scientists and applied mathematicians developing the technology and tools needed to address those problems. The SciDAC program has played an increasingly important role in scientific research by allowing scientists to create more accurate models of complex processes, simulate problems once thought to be impossible, and analyze the growing amount of data generated by experiments. To help further the research community's ability to tap into the capabilities of current and future supercomputers, Under Secretary for Science, Raymond Orbach, launched the Innovative and Novel Computational Impact on Theory and Experiment (INCITE) program in 2003. The INCITE program was conceived specifically to seek out computationally intensive, large-scale research projects with the potential to significantly advance key areas in science and engineering. The program encourages proposals from universities, other research institutions, and industry. During the first two years of the INCITE program, 10 percent of the resources at NERSC were allocated to INCITE awardees. However, demand for supercomputing resources

Comparison of DAC and MONACO DSMC Codes with Flat Plate Simulation

NASA Technical Reports Server (NTRS)

Padilla, Jose F.

2010-01-01

Various implementations of the direct simulation Monte Carlo (DSMC) method exist in academia, government and industry. By comparing implementations, deficiencies and merits of each can be discovered. This document reports comparisons between DSMC Analysis Code (DAC) and MONACO. DAC is NASA's standard DSMC production code and MONACO is a research DSMC code developed in academia. These codes have various differences; in particular, they employ distinct computational grid definitions. In this study, DAC and MONACO are compared by having each simulate a blunted flat plate wind tunnel test, using an identical volume mesh. Simulation expense and DSMC metrics are compared. In addition, flow results are compared with available laboratory data. Overall, this study revealed that both codes, excluding grid adaptation, performed similarly. For parallel processing, DAC was generally more efficient. As expected, code accuracy was mainly dependent on physical models employed.

New User Support in the University Network with DACS Scheme

ERIC Educational Resources Information Center

Odagiri, Kazuya; Yaegashi, Rihito; Tadauchi, Masaharu; Ishii, Naohiro

2007-01-01

Purpose: The purpose of this paper is to propose and examine the new user support in university network. Design/methodology/approach: The new user support is realized by use of DACS (Destination Addressing Control System) Scheme which manages a whole network system through communication control on a client computer. This DACS Scheme has been…

Air Data - Concentration Map

EPA Pesticide Factsheets

Make a map of daily concentrations over several days. The daily air quality can be displayed in terms of the Air Quality Index or in concentration ranges for certain PM species like organic carbon, nitrates, and sulfates.

OPENING REMARKS: SciDAC: Scientific Discovery through Advanced Computing

NASA Astrophysics Data System (ADS)

Strayer, Michael

2005-01-01

Good morning. Welcome to SciDAC 2005 and San Francisco. SciDAC is all about computational science and scientific discovery. In a large sense, computational science characterizes SciDAC and its intent is change. It transforms both our approach and our understanding of science. It opens new doors and crosses traditional boundaries while seeking discovery. In terms of twentieth century methodologies, computational science may be said to be transformational. There are a number of examples to this point. First are the sciences that encompass climate modeling. The application of computational science has in essence created the field of climate modeling. This community is now international in scope and has provided precision results that are challenging our understanding of our environment. A second example is that of lattice quantum chromodynamics. Lattice QCD, while adding precision and insight to our fundamental understanding of strong interaction dynamics, has transformed our approach to particle and nuclear science. The individual investigator approach has evolved to teams of scientists from different disciplines working side-by-side towards a common goal. SciDAC is also undergoing a transformation. This meeting is a prime example. Last year it was a small programmatic meeting tracking progress in SciDAC. This year, we have a major computational science meeting with a variety of disciplines and enabling technologies represented. SciDAC 2005 should position itself as a new corner stone for Computational Science and its impact on science. As we look to the immediate future, FY2006 will bring a new cycle to SciDAC. Most of the program elements of SciDAC will be re-competed in FY2006. The re-competition will involve new instruments for computational science, new approaches for collaboration, as well as new disciplines. There will be new opportunities for virtual experiments in carbon sequestration, fusion, and nuclear power and nuclear waste, as well as collaborations

Opening Comments: SciDAC 2009

NASA Astrophysics Data System (ADS)

Strayer, Michael

2009-07-01

Welcome to San Diego and the 2009 SciDAC conference. Over the next four days, I would like to present an assessment of the SciDAC program. We will look at where we've been, how we got to where we are and where we are going in the future. Our vision is to be first in computational science, to be best in class in modeling and simulation. When Ray Orbach asked me what I would do, in my job interview for the SciDAC Director position, I said we would achieve that vision. And with our collective dedicated efforts, we have managed to achieve this vision. In the last year, we have now the most powerful supercomputer for open science, Jaguar, the Cray XT system at the Oak Ridge Leadership Computing Facility (OLCF). We also have NERSC, probably the best-in-the-world program for productivity in science that the Office of Science so depends on. And the Argonne Leadership Computing Facility offers architectural diversity with its IBM Blue Gene/P system as a counterbalance to Oak Ridge. There is also ESnet, which is often understated—the 40 gigabit per second dual backbone ring that connects all the labs and many DOE sites. In the President's Recovery Act funding, there is exciting news that ESnet is going to build out to a 100 gigabit per second network using new optical technologies. This is very exciting news for simulations and large-scale scientific facilities. But as one noted SciDAC luminary said, it's not all about the computers—it's also about the science—and we are also achieving our vision in this area. Together with having the fastest supercomputer for science, at the SC08 conference, SciDAC researchers won two ACM Gordon Bell Prizes for the outstanding performance of their applications. The DCA++ code, which solves some very interesting problems in materials, achieved a sustained performance of 1.3 petaflops, an astounding result and a mark I suspect will last for some time. The LS3DF application for studying nanomaterials also required the development of a

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

A rigorous analysis of digital pre-emphasis and DAC resolution for interleaved DAC Nyquist-WDM signal generation in high-speed coherent optical transmission systems

NASA Astrophysics Data System (ADS)

Weng, Yi; Wang, Junyi; He, Xuan; Pan, Zhongqi

2018-02-01

The Nyquist spectral shaping techniques facilitate a promising solution to enhance spectral efficiency (SE) and further reduce the cost-per-bit in high-speed wavelength-division multiplexing (WDM) transmission systems. Hypothetically, any Nyquist WDM signals with arbitrary shapes can be generated by the use of the digital signal processing (DSP) based electrical filters (E-filter). Nonetheless, in actual 100G/ 200G coherent systems, the performance as well as DSP complexity are increasingly restricted by cost and power consumption. Henceforward it is indispensable to optimize DSP to accomplish the preferred performance at the least complexity. In this paper, we systematically investigated the minimum requirements and challenges of Nyquist WDM signal generation, particularly for higher-order modulation formats, including 16 quadrature amplitude modulation (QAM) or 64QAM. A variety of interrelated parameters, such as channel spacing and roll-off factor, have been evaluated to optimize the requirements of the digital-to-analog converter (DAC) resolution and transmitter E-filter bandwidth. The impact of spectral pre-emphasis has been predominantly enhanced via the proposed interleaved DAC architecture by at least 4%, and hence reducing the required optical signal to noise ratio (OSNR) at a bit error rate (BER) of 10-3 by over 0.45 dB at a channel spacing of 1.05 symbol rate and an optimized roll-off factor of 0.1. Furthermore, the requirements of sampling rate for different types of super-Gaussian E-filters are discussed for 64QAM Nyquist WDM transmission systems. Finally, the impact of the non-50% duty cycle error between sub-DACs upon the quality of the generated signals for the interleaved DAC structure has been analyzed.

Performance Engineering Research Institute SciDAC-2 Enabling Technologies Institute Final Report

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

Lucas, Robert

2013-04-20

Enhancing the performance of SciDAC applications on petascale systems had high priority within DOE SC at the start of the second phase of the SciDAC program, SciDAC-2, as it continues to do so today. Achieving expected levels of performance on high-end computing (HEC) systems is growing ever more challenging due to enormous scale, increasing architectural complexity, and increasing application complexity. To address these challenges, the University of Southern California?s Information Sciences Institute organized the Performance Engineering Research Institute (PERI). PERI implemented a unified, tripartite research plan encompassing: (1) performance modeling and prediction; (2) automatic performance tuning; and (3) performance engineeringmore » of high profile applications. Within PERI, USC?s primary research activity was automatic tuning (autotuning) of scientific software. This activity was spurred by the strong user preference for automatic tools and was based on previous successful activities such as ATLAS, which automatically tuned components of the LAPACK linear algebra library, and other recent work on autotuning domain-specific libraries. Our other major component was application engagement, to which we devoted approximately 30% of our effort to work directly with SciDAC-2 applications. This report is a summary of the overall results of the USC PERI effort.« less

Modeling and optimal design of CO2 Direct Air Capture systems in large arrays

NASA Astrophysics Data System (ADS)

Sadri Irani, Samaneh; Luzzatto-Fegiz, Paolo

2017-11-01

As noted by the 2014 IPCC report, while the rise in atmospheric CO2 would be slowed by emissions reductions, removing atmospheric CO2 is an important part of possible paths to climate stabilization. Direct Air Capture of CO2 with chemicals (DAC) is one of several proposed carbon capture technologies. There is an ongoing debate on whether DAC is an economically viable approach to alleviate climate change. In addition, like all air capture strategies, DAC is strongly constrained by the net-carbon problem, namely the need to control CO2 emissions associated with the capture process (for example, if DAC not powered by renewables). Research to date has focused on the chemistry and economics of individual DAC devices. However, the fluid mechanics of their large-scale deployment has not been examined in the literature, to the best of our knowledge. In this presentation, we develop a model for flow through an array of DAC devices, varying their lateral extent and their separation. We build on a recent theory of canopy flows, introducing terms for CO2 entrainment into the array boundary layer, and transport into the farm. In addition, we examine the possibility of driving flow passively by wind, thereby reducing energy consumption. The optimal operational design is established considering the total cost, drag force, energy consumption and total CO2 capture.

Design of integrated all optical digital to analog converter (DAC) using 2D photonic crystals

NASA Astrophysics Data System (ADS)

Moniem, Tamer A.; El-Din, Eman S.

2017-11-01

A novel design of all optical 3 bit digital to analog (DAC) converter will be presented in this paper based on 2 Dimension photonic crystals (PhC). The proposed structure is based on the photonic crystal ring resonators (PCRR) with combining the nonlinear Kerr effect on the PCRR. The total size of the proposed optical 3 bit DAC is equal to 44 μm × 37 μm of 2D square lattice photonic crystals of silicon rods with refractive index equal to 3.4. The finite different time domain (FDTD) and Plane Wave Expansion (PWE) methods are used to back the overall operation of the proposed optical DAC.

A high performance DAC /DDS daughter module for the RHIC LLRF platform

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

Hayes, T.; Harvey, M.; Narayan, G.

The RHIC LLRF upgrade is a flexible, modular system. Output signals are generated by a custom designed XMC card with 4 high speed digital to analog (DAC) converters interfaced to a high performance field programmable gate array (FPGA). This paper discusses the hardware details of the XMC DAC board as well as the implementation of a low noise rf synthesizer with digital IQ modulation. This synthesizer also provides injection phase cogging and frequency hop rebucketing capabilities. A new modular RHIC LLRF system was recently designed and commissioned based on custom designed XMC cards. As part of that effort a highmore » speed, four channel DAC board was designed. The board uses Maxim MAX5891 16 bit DACs with a maximum update rate of 600 Msps. Since this module is intended to be used for many different systems throughout the Collider Accelerator complex, it was designed to be as generic as possible. One major application of this DAC card is to implement digital synthesizers to provide drive signals to the various cavities at RHIC. Since RHIC is a storage ring with stores that typically last many hours, extremely low RF noise is a critical requirement. Synchrotron frequencies at RHIC range from a few hertz to several hundred hertz depending on the species and point in the acceleration cycle so close in phase noise is a major concern. The RHIC LLRF system uses the Update Link, a deterministic, high speed data link that broadcasts the revolution frequency and the synchronous phase angle. The digital synthesizers use this data to generate a properly phased analog drive signal. The synthesizers must also provide smooth phase shifts for cogging and support frequency shift rebucketing. One additional feature implemented in the FPGA is a digital waveform generator (WFG) that generates I and Q data pairs based on a user selected amplitude and phase profile as a function of time.« less

Evaluation of continuous air monitor placement in a plutonium facility.

PubMed

Whicker, J J; Rodgers, J C; Fairchild, C I; Scripsick, R C; Lopez, R C

1997-05-01

Department of Energy appraisers found continuous air monitors at Department of Energy plutonium facilities alarmed less than 30% of the time when integrated room plutonium air concentrations exceeded 500 DAC-hours. Without other interventions, this alarm percentage suggests the possibility that workers could be exposed to high airborne concentrations without continuous air monitor alarms. Past research has shown that placement of continuous air monitors is a critical component in rapid and reliable detection of airborne releases. At Los Alamos National Laboratory and many other Department of Energy plutonium facilities, continuous air monitors have been primarily placed at ventilation exhaust points. The purpose of this study was to evaluate and compare the effectiveness of exhaust register placement of workplace continuous air monitors with other sampling locations. Polydisperse oil aerosols were released from multiple locations in two plutonium laboratories at Los Alamos National Laboratory. An array of laser particle counters positioned in the rooms measured time-resolved aerosol dispersion. Results showed alternative placement of air samplers generally resulted in aerosol detection that was faster, often more sensitive, and equally reliable compared with samplers at exhaust registers.

Design of the low area monotonic trim DAC in 40 nm CMOS technology for pixel readout chips

NASA Astrophysics Data System (ADS)

Drozd, A.; Szczygiel, R.; Maj, P.; Satlawa, T.; Grybos, P.

2014-12-01

The recent research in hybrid pixel detectors working in single photon counting mode focuses on nanometer or 3D technologies which allow making pixels smaller and implementing more complex solutions in each of the pixels. Usually single pixel in readout electronics for X-ray detection comprises of charge amplifier, shaper and discriminator that allow classification of events occurring at the detector as true or false hits by comparing amplitude of the signal obtained with threshold voltage, which minimizes the influence of noise effects. However, making the pixel size smaller often causes problems with pixel to pixel uniformity and additional effects like charge sharing become more visible. To improve channel-to-channel uniformity or implement an algorithm for charge sharing effect minimization, small area trimming DACs working in each pixel independently are necessary. However, meeting the requirement of small area often results in poor linearity and even non-monotonicity. In this paper we present a novel low-area thermometer coded 6-bit DAC implemented in 40 nm CMOS technology. Monte Carlo simulations were performed on the described design proving that under all conditions designed DAC is inherently monotonic. Presented DAC was implemented in the prototype readout chip with 432 pixels working in single photon counting mode, with two trimming DACs in each pixel. Each DAC occupies the area of 8 μm × 18.5 μm. Measurements and chips' tests were performed to obtain reliable statistical results.

Acceleration of the chemistry solver for modeling DI engine combustion using dynamic adaptive chemistry (DAC) schemes

NASA Astrophysics Data System (ADS)

Shi, Yu; Liang, Long; Ge, Hai-Wen; Reitz, Rolf D.

2010-03-01

Acceleration of the chemistry solver for engine combustion is of much interest due to the fact that in practical engine simulations extensive computational time is spent solving the fuel oxidation and emission formation chemistry. A dynamic adaptive chemistry (DAC) scheme based on a directed relation graph error propagation (DRGEP) method has been applied to study homogeneous charge compression ignition (HCCI) engine combustion with detailed chemistry (over 500 species) previously using an R-value-based breadth-first search (RBFS) algorithm, which significantly reduced computational times (by as much as 30-fold). The present paper extends the use of this on-the-fly kinetic mechanism reduction scheme to model combustion in direct-injection (DI) engines. It was found that the DAC scheme becomes less efficient when applied to DI engine simulations using a kinetic mechanism of relatively small size and the accuracy of the original DAC scheme decreases for conventional non-premixed combustion engine. The present study also focuses on determination of search-initiating species, involvement of the NOx chemistry, selection of a proper error tolerance, as well as treatment of the interaction of chemical heat release and the fuel spray. Both the DAC schemes were integrated into the ERC KIVA-3v2 code, and simulations were conducted to compare the two schemes. In general, the present DAC scheme has better efficiency and similar accuracy compared to the previous DAC scheme. The efficiency depends on the size of the chemical kinetics mechanism used and the engine operating conditions. For cases using a small n-heptane kinetic mechanism of 34 species, 30% of the computational time is saved, and 50% for a larger n-heptane kinetic mechanism of 61 species. The paper also demonstrates that by combining the present DAC scheme with an adaptive multi-grid chemistry (AMC) solver, it is feasible to simulate a direct-injection engine using a detailed n-heptane mechanism with 543 species

Membrane topology and identification of key residues of EaDAcT, a plant MBOAT with unusual substrate specificity.

PubMed

Tran, Tam N T; Shelton, Jennifer; Brown, Susan; Durrett, Timothy P

2017-10-01

Euonymus alatus diacylglycerol acetyltransferase (EaDAcT) catalyzes the transfer of an acetyl group from acetyl-CoA to the sn-3 position of diacylglycerol to form 3-acetyl-1,2-diacyl-sn-glycerol (acetyl-TAG). EaDAcT belongs to a small, plant-specific subfamily of the membrane bound O-acyltransferases (MBOAT) that acylate different lipid substrates. Sucrose gradient density centrifugation revealed that EaDAcT colocalizes to the same fractions as an endoplasmic reticulum (ER)-specific marker. By mapping the membrane topology of EaDAcT, we obtained an experimentally determined topology model for a plant MBOAT. The EaDAcT model contains four transmembrane domains (TMDs), with both the N- and C-termini orientated toward the lumen of the ER. In addition, there is a large cytoplasmic loop between the first and second TMDs, with the MBOAT signature region of the protein embedded in the third TMD close to the interface between the membrane and the cytoplasm. During topology mapping, we discovered two cysteine residues (C187 and C293) located on opposite sides of the membrane that are important for enzyme activity. In order to identify additional amino acid residues important for acetyltransferase activity, we isolated and characterized acetyltransferases from other acetyl-TAG-producing plants. Among them, the acetyltransferase from Euonymus fortunei possessed the highest activity in vivo and in vitro. Mutagenesis of conserved amino acids revealed that S253, H257, D258 and V263 are essential for EaDAcT activity. Alteration of residues unique to the acetyltransferases did not alter the unique acyl donor specificity of EaDAcT, suggesting that multiple amino acids are important for substrate recognition. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

Biologically plausible particulate air pollution mortality concentration-response functions.

PubMed Central

Roberts, Steven

2004-01-01

In this article I introduce an alternative method for estimating particulate air pollution mortality concentration-response functions. This method constrains the particulate air pollution mortality concentration-response function to be biologically plausible--that is, a non-decreasing function of the particulate air pollution concentration. Using time-series data from Cook County, Illinois, the proposed method yields more meaningful particulate air pollution mortality concentration-response function estimates with an increase in statistical accuracy. PMID:14998745

32 CFR 637.2 - Use of MPI and DAC Detectives/Investigators.

Code of Federal Regulations, 2010 CFR

2010-07-01

.../investigators may be employed in joint MPI/USACIDC drug suppression teams; however, the conduct of such... and DAC detectives/investigators may also be utilized to make controlled buys of suspected controlled...

20 Years of Air-Water Gas Exchange Observations for Pesticides in the Western Arctic Ocean.

PubMed

Jantunen, Liisa M; Wong, Fiona; Gawor, Anya; Kylin, Henrik; Helm, Paul A; Stern, Gary A; Strachan, William M J; Burniston, Deborah A; Bidleman, Terry F

2015-12-01

The Arctic has been contaminated by legacy organochlorine pesticides (OCPs) and currently used pesticides (CUPs) through atmospheric transport and oceanic currents. Here we report the time trends and air-water exchange of OCPs and CUPs from research expeditions conducted between 1993 and 2013. Compounds determined in both air and water were trans- and cis-chlordanes (TC, CC), trans- and cis-nonachlors (TN, CN), heptachlor exo-epoxide (HEPX), dieldrin (DIEL), chlorobornanes (ΣCHBs and toxaphene), dacthal (DAC), endosulfans and metabolite endosulfan sulfate (ENDO-I, ENDO-II, and ENDO SUL), chlorothalonil (CHT), chlorpyrifos (CPF), and trifluralin (TFN). Pentachloronitrobenzene (PCNB and quintozene) and its soil metabolite pentachlorothianisole (PCTA) were also found in air. Concentrations of most OCPs declined in surface water, whereas some CUPs increased (ENDO-I, CHT, and TFN) or showed no significant change (CPF and DAC), and most compounds declined in air. Chlordane compound fractions TC/(TC + CC) and TC/(TC + CC + TN) decreased in water and air, while CC/(TC + CC + TN) increased. TN/(TC + CC + TN) also increased in air and slightly, but not significantly, in water. These changes suggest selective removal of more labile TC and/or a shift in chlordane sources. Water-air fugacity ratios indicated net volatilization (FR > 1.0) or near equilibrium (FR not significantly different from 1.0) for most OCPs but net deposition (FR < 1.0) for ΣCHBs. Net deposition was shown for ENDO-I on all expeditions, while the net exchange direction of other CUPs varied. Understanding the processes and current state of air-surface exchange helps to interpret environmental exposure and evaluate the effectiveness of international protocols and provides insights for the environmental fate of new and emerging chemicals.

Dynamic airspace configuration algorithms for next generation air transportation system

NASA Astrophysics Data System (ADS)

Wei, Jian

The National Airspace System (NAS) is under great pressure to safely and efficiently handle the record-high air traffic volume nowadays, and will face even greater challenge to keep pace with the steady increase of future air travel demand, since the air travel demand is projected to increase to two to three times the current level by 2025. The inefficiency of traffic flow management initiatives causes severe airspace congestion and frequent flight delays, which cost billions of economic losses every year. To address the increasingly severe airspace congestion and delays, the Next Generation Air Transportation System (NextGen) is proposed to transform the current static and rigid radar based system to a dynamic and flexible satellite based system. New operational concepts such as Dynamic Airspace Configuration (DAC) have been under development to allow more flexibility required to mitigate the demand-capacity imbalances in order to increase the throughput of the entire NAS. In this dissertation, we address the DAC problem in the en route and terminal airspace under the framework of NextGen. We develop a series of algorithms to facilitate the implementation of innovative concepts relevant with DAC in both the en route and terminal airspace. We also develop a performance evaluation framework for comprehensive benefit analyses on different aspects of future sector design algorithms. First, we complete a graph based sectorization algorithm for DAC in the en route airspace, which models the underlying air route network with a weighted graph, converts the sectorization problem into the graph partition problem, partitions the weighted graph with an iterative spectral bipartition method, and constructs the sectors from the partitioned graph. The algorithm uses a graph model to accurately capture the complex traffic patterns of the real flights, and generates sectors with high efficiency while evenly distributing the workload among the generated sectors. We further improve

A new air quality monitoring and early warning system: Air quality assessment and air pollutant concentration prediction.

PubMed

Yang, Zhongshan; Wang, Jian

2017-10-01

Air pollution in many countries is worsening with industrialization and urbanization, resulting in climate change and affecting people's health, thus, making the work of policymakers more difficult. It is therefore both urgent and necessary to establish amore scientific air quality monitoring and early warning system to evaluate the degree of air pollution objectively, and predict pollutant concentrations accurately. However, the integration of air quality assessment and air pollutant concentration prediction to establish an air quality system is not common. In this paper, we propose a new air quality monitoring and early warning system, including an assessment module and forecasting module. In the air quality assessment module, fuzzy comprehensive evaluation is used to determine the main pollutants and evaluate the degree of air pollution more scientifically. In the air pollutant concentration prediction module, a novel hybridization model combining complementary ensemble empirical mode decomposition, a modified cuckoo search and differential evolution algorithm, and an Elman neural network, is proposed to improve the forecasting accuracy of six main air pollutant concentrations. To verify the effectiveness of this system, pollutant data for two cities in China are used. The result of the fuzzy comprehensive evaluation shows that the major air pollutants in Xi'an and Jinan are PM 10 and PM 2.5 respectively, and that the air quality of Xi'an is better than that of Jinan. The forecasting results indicate that the proposed hybrid model is remarkably superior to all benchmark models on account of its higher prediction accuracy and stability. Copyright © 2017 Elsevier Inc. All rights reserved.

Final Report for DOE Project: Portal Web Services: Support of DOE SciDAC Collaboratories

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

Mary Thomas, PI; Geoffrey Fox, Co-PI; Gannon, D

2007-10-01

Grid portals provide the scientific community with familiar and simplified interfaces to the Grid and Grid services, and it is important to deploy grid portals onto the SciDAC grids and collaboratories. The goal of this project is the research, development and deployment of interoperable portal and web services that can be used on SciDAC National Collaboratory grids. This project has four primary task areas: development of portal systems; management of data collections; DOE science application integration; and development of web and grid services in support of the above activities.

An embodied biologically constrained model of foraging: from classical and operant conditioning to adaptive real-world behavior in DAC-X.

PubMed

Maffei, Giovanni; Santos-Pata, Diogo; Marcos, Encarni; Sánchez-Fibla, Marti; Verschure, Paul F M J

2015-12-01

Animals successfully forage within new environments by learning, simulating and adapting to their surroundings. The functions behind such goal-oriented behavior can be decomposed into 5 top-level objectives: 'how', 'why', 'what', 'where', 'when' (H4W). The paradigms of classical and operant conditioning describe some of the behavioral aspects found in foraging. However, it remains unclear how the organization of their underlying neural principles account for these complex behaviors. We address this problem from the perspective of the Distributed Adaptive Control theory of mind and brain (DAC) that interprets these two paradigms as expressing properties of core functional subsystems of a layered architecture. In particular, we propose DAC-X, a novel cognitive architecture that unifies the theoretical principles of DAC with biologically constrained computational models of several areas of the mammalian brain. DAC-X supports complex foraging strategies through the progressive acquisition, retention and expression of task-dependent information and associated shaping of action, from exploration to goal-oriented deliberation. We benchmark DAC-X using a robot-based hoarding task including the main perceptual and cognitive aspects of animal foraging. We show that efficient goal-oriented behavior results from the interaction of parallel learning mechanisms accounting for motor adaptation, spatial encoding and decision-making. Together, our results suggest that the H4W problem can be solved by DAC-X building on the insights from the study of classical and operant conditioning. Finally, we discuss the advantages and limitations of the proposed biologically constrained and embodied approach towards the study of cognition and the relation of DAC-X to other cognitive architectures. Copyright © 2015 Elsevier Ltd. All rights reserved.

Measuring Concentrations of Particulate 140La in the Air

DOE PAGES

Okada, Colin E.; Kernan, Warnick J.; Keillor, Martin E.; ...

2016-05-01

Air sampling systems were deployed to measure the concentration of radioactive material in the air during the Full-Scale Radiological Dispersal Device experiments. The air samplers were positioned 100-600 meters downwind of the release point. The filters were collected immediately and analyzed in the field. Quantities for total activity collected on the air filters are reported along with additional information to compute the average or integrated air concentrations.

The impact of SciDAC on US climate change research and the IPCCAR4

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

Wehner, Michael

2005-07-08

SciDAC has invested heavily in climate change research. We offer a candid opinion as to the impact of the DOE laboratories' SciDAC projects on the upcoming Fourth Assessment Report of the Intergovernmental Panel on Climate Change. As a result of the direct importance of climate change to society, climate change research is highly coordinated at the international level. The Intergovernmental Panel on Climate Change (IPCC) is charged with providing regular reports on the state of climate change research to government policymakers. These reports are the product of thousands of scientists efforts. A series of reviews involving both scientists and policymakersmore » make them among the most reviewed documents produced in any scientific field. The high profile of these reports acts a driver to many researchers in the climate sciences. The Fourth Assessment Report (AR4) is scheduled to be released in 2007. SciDAC sponsored research has enabled the United States climate modeling community to make significant contributions to this report. Two large multi-Laboratory SciDAC projects are directly relevant to the activities of the IPCC. The first, entitled ''Collaborative Design and Development of the Community Climate System Model for Terascale Computers'', has made important software contributions to the recently released third version of the Community Climate System Model (CCSM3.0) developed at the National Center for Atmospheric Research. This is a multi-institutional project involving Los Alamos National Laboratory, Oak Ridge National Laboratory, Lawrence Berkeley National Laboratory, Pacific Northwest National Laboratory, Argonne National Laboratory, Lawrence Livermore National Laboratory and the National Center for Atmospheric Research. The original principal investigators were Robert Malone and John B. Drake. The current principal investigators are Phil Jones and John B. Drake. The second project, entitled ''Earth System Grid II: Turning Climate Datasets into

Phase relations in the system Fe-Si determined in an internally-resistive heated DAC

NASA Astrophysics Data System (ADS)

Komabayashi, T.; Antonangeli, D.; Morard, G.; Sinmyo, R.; Mezouar, N.

2015-12-01

It is believed that the iron-rich Earth's core contains some amounts of light elements on the basis of the density deficit of 7 % compared to pure iron. The identification of the kinds and amounts of the light elements in the core places constraints on the origin, formation, and evolution of the Earth because dissolution of light elements into an iron-rich core should place important constraints on the thermodynamic conditions (pressure (P), temperature (T), and oxygen fugacity) of the equilibration between liquid silicate and liquid iron during the core formation. Among potential light elements, silicon has been attracting attentions because it is abundant in the mantle, partitioned into both solid and liquid irons, and very sensitive to the oxygen fugacity. An important phase relation in iron alloy is a transition between the face-centred cubic (FCC) structure and hexagonal close-packed (HCP) structure. This boundary is a key to infer the stable structure in the inner core and is used to derive thermodynamic properties of the phases (Komabayashi, 2014). In the Fe-Si system, previous reports were based on experiments in laser-heated diamond anvil cells (DAC), which might have included large termperature uncertainties. We have revisited this boundary in the system Fe-Si using an internally resistive-heated DAC combined with synchrotron X-ray diffraction at the beamline ID27, ESRF. The internally-heated DAC (Komabayashi et al., 2009; 2012) provides much more stable heating than the laser-heated DAC and much higher temperature than externally resistive-heated DAC, which enables us to place tight constraints on the P-T locations of the boundaries. Also because the minimum measurable temperature is as low as 1000 K due to the stable electric heating, the internal heating is able to examine the low temperature phase stability which was not studied by the previous studies. We will report the P-T locations of the boundaries and evaluate the effect of Si on the phase

Fractal Analysis of Air Pollutant Concentrations

NASA Astrophysics Data System (ADS)

Cortina-Januchs, M. G.; Barrón-Adame, J. M.; Vega-Corona, A.; Andina, D.

2010-05-01

Air pollution poses significant threats to human health and the environment throughout the developed and developing countries. This work focuses on fractal analysis of pollutant concentration in Salamanca, Mexico. The city of Salamanca has been catalogued as one of the most polluted cities in Mexico. The main causes of pollution in this city are fixed emission sources, such as chemical industry and electricity generation. Sulphur Dioxide (SO2) and Particulate Matter less than 10 micrometer in diameter (PM10) are the most important pollutants in this region. Air pollutant concentrations were investigated by applying the box counting method in time series obtained of the Automatic Environmental Monitoring Network (AEMN). One year of time series of hourly average concentrations were analyzed in order to characterize the temporal structures of SO2 and PM10.

A 6-bit 4 GS/s pseudo-thermometer segmented CMOS DAC

NASA Astrophysics Data System (ADS)

Yijun, Song; Wenyuan, Li

2014-06-01

A 6-bit 4 GS/s, high-speed and power-efficient DAC for ultra-high-speed transceivers in 60 GHz band millimeter wave technology is presented. A novel pseudo-thermometer architecture is proposed to realize a good compromise between the fast conversion speed and the chip area. Symmetrical and compact floor planning and layout techniques including tree-like routing, cross-quading and common-centroid method are adopted to guarantee the chip is fully functional up to near-Nyquist frequency in a standard 0.18 μm CMOS process. Post simulation results corroborate the feasibility of the designed DAC, which canperform good static and dynamic linearity without calibration. DNL errors and INL errors can be controlled within ±0.28 LSB and ±0.26 LSB, respectively. SFDR at 4 GHz clock frequency for a 1.9 GHz near-Nyquist sinusoidal output signal is 40.83 dB and the power dissipation is less than 37 mW.

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.

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

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

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-generatingmore » 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.« less

Detectability of neural tracts and nuclei in the brainstem utilizing 3DAC-PROPELLER.

PubMed

Nishikawa, Taro; Okamoto, Kouichirou; Matsuzawa, Hitoshi; Terumitsu, Makoto; Nakada, Tsutomu; Fujii, Yukihiko

2014-01-01

Despite clinical importance of identifying exact anatomical location of neural tracts and nuclei in the brainstem, no neuroimaging studies have validated the detectability of these structures. The aim of this study was to assess the detectability of the structures using three-dimensional anisotropy contrast-periodically rotated overlapping parallel lines with enhanced reconstruction (3DAC-PROPELLER) imaging. Forty healthy volunteers (21 males, 19 females; 19-53 years, average 23.4 years) participated in this study. 3DAC-PROPELLER axial images were obtained with a 3T-MR system at four levels of the brainstem: the lower midbrain, upper and lower pons, and medulla oblongata. Three experts independently judged whether five tracts (corticospinal tract, medial lemniscus, medial longitudinal fasciculus, central tegmental and spinothalamic tracts) and 10 nuclei (oculomotor and trochlear nuclei, spinal trigeminal, abducens, facial, vestibular, hypoglossal, prepositus, and solitary nuclei, locus ceruleus, superior and inferior olives) on each side could be identified. In total, 240 assessments were made. The five tracts and eight nuclei were identified in all the corresponding assessments, whereas the locus ceruleus and superior olive could not be identified in 3 (1.3%) and 16 (6.7%) assessments, respectively. 3DAC-PROPELLER seems extremely valuable imaging method for mapping out surgical strategies for brainstem lesions. Copyright © 2013 by the American Society of Neuroimaging.

Influence of air humidity and the distance from the source on negative air ion concentration in indoor air.

PubMed

Wu, Chih Cheng; Lee, Grace W M; Yang, Shinhao; Yu, Kuo-Pin; Lou, Chia Ling

2006-10-15

Although negative air ionizer is commonly used for indoor air cleaning, few studies examine the concentration gradient of negative air ion (NAI) in indoor environments. This study investigated the concentration gradient of NAI at various relative humidities and distances form the source in indoor air. The NAI was generated by single-electrode negative electric discharge; the discharge was kept at dark discharge and 30.0 kV. The NAI concentrations were measured at various distances (10-900 cm) from the discharge electrode in order to identify the distribution of NAI in an indoor environment. The profile of NAI concentration was monitored at different relative humidities (38.1-73.6% RH) and room temperatures (25.2+/-1.4 degrees C). Experimental results indicate that the influence of relative humidity on the concentration gradient of NAI was complicated. There were four trends for the relationship between NAI concentration and relative humidity at different distances from the discharge electrode. The changes of NAI concentration with an increase in relative humidity at different distances were quite steady (10-30 cm), strongly declining (70-360 cm), approaching stability (420-450 cm) and moderately increasing (560-900 cm). Additionally, the regression analysis of NAI concentrations and distances from the discharge electrode indicated a logarithmic linear (log-linear) relationship; the distance of log-linear tendency (lambda) decreased with an increase in relative humidity such that the log-linear distance of 38.1% RH was 2.9 times that of 73.6% RH. Moreover, an empirical curve fit based on this study for the concentration gradient of NAI generated by negative electric discharge in indoor air was developed for estimating the NAI concentration at different relative humidities and distances from the source of electric discharge.

10 CFR 835.209 - Concentrations of radioactive material in air.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 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 and External Exposure § 835.209 Concentrations of radioactive material in air. (a) The derived air...

10 CFR 835.209 - Concentrations of radioactive material in air.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 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 and External Exposure § 835.209 Concentrations of radioactive material in air. (a) The derived air...

10 CFR 835.209 - Concentrations of radioactive material in air.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 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 and External Exposure § 835.209 Concentrations of radioactive material in air. (a) The derived air...

10 CFR 835.209 - Concentrations of radioactive material in air.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 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 and External Exposure § 835.209 Concentrations of radioactive material in air. (a) The derived air...

Fractional kalman filter to estimate the concentration of air pollution

NASA Astrophysics Data System (ADS)

Vita Oktaviana, Yessy; Apriliani, Erna; Khusnul Arif, Didik

2018-04-01

Air pollution problem gives important effect in quality environment and quality of human’s life. Air pollution can be caused by nature sources or human activities. Pollutant for example Ozone, a harmful gas formed by NOx and volatile organic compounds (VOCs) emitted from various sources. The air pollution problem can be modeled by TAPM-CTM (The Air Pollution Model with Chemical Transport Model). The model shows concentration of pollutant in the air. Therefore, it is important to estimate concentration of air pollutant. Estimation method can be used for forecast pollutant concentration in future and keep stability of air quality. In this research, an algorithm is developed, based on Fractional Kalman Filter to solve the model of air pollution’s problem. The model will be discretized first and then it will be estimated by the method. The result shows that estimation of Fractional Kalman Filter has better accuracy than estimation of Kalman Filter. The accuracy was tested by applying RMSE (Root Mean Square Error).

The potential of a dielectrophoresis activated cell sorter (DACS) as a next generation cell sorter

NASA Astrophysics Data System (ADS)

Lee, Dongkyu; Hwang, Bohyun; Kim, Byungkyu

2016-12-01

Originally introduced by H. A. Pohl in 1951, dielectrophoretic (DEP) force has been used as a striking tool for biological particle manipulation (or separation) for the last few decades. In particular, dielectrophoresis activated cell sorters (DACSes) have been developed for applications in various biomedical fields. These applications include cell replacement therapy, drug screening and medical diagnostics. Since a DACS does not require a specific bio-marker, it is able to function as a biological particle sorting tool with numerous configurations for various cells [e.g. red blood cells (RBCs), white blood cells (WBCs), circulating tumor cells, leukemia cells, breast cancer cells, bacterial cells, yeast cells and sperm cells]. This article explores current DACS capabilities worldwide, and it also looks at recent developments intended to overcome particular limitations. First, the basic theories are reviewed. Then, representative DACSes based on DEP trapping, traveling wave DEP systems, DEP field-flow fractionation and DEP barriers are introduced, and the strong and weak points of each DACS are discussed. Finally, for the purposes of commercialization, prerequisites regarding throughput, efficiency and recovery rates are discussed in detail through comparisons with commercial cell sorters (e.g. fluorescent activated and magnetic activated cell sorters).

Security and Privacy in a DACS.

PubMed

Delgado, Jaime; Llorente, Silvia; Pàmies, Martí; Vilalta, Josep

2016-01-01

The management of electronic health records (EHR), in general, and clinical documents, in particular, is becoming a key issue in the daily work of Healthcare Organizations (HO). The need for providing secure and private access to, and storage for, clinical documents together with the need for HO to interoperate, raises a number of issues difficult to solve. Many systems are in place to manage EHR and documents. Some of these Healthcare Information Systems (HIS) follow standards in their document structure and communications protocols, but many do not. In fact, they are mostly proprietary and do not interoperate. Our proposal to solve the current situation is the use of a DACS (Document Archiving and Communication System) for providing security, privacy and standardized access to clinical documents.

Dynamic diamond anvil cell (dDAC): A novel device for studying the dynamic-pressure properties of materials

NASA Astrophysics Data System (ADS)

Evans, William J.; Yoo, Choong-Shik; Lee, Geun Woo; Cynn, Hyunchae; Lipp, Magnus J.; Visbeck, Ken

2007-07-01

We have developed a unique device, a dynamic diamond anvil cell (dDAC), which repetitively applies a time-dependent load/pressure profile to a sample. This capability allows studies of the kinetics of phase transitions and metastable phases at compression (strain) rates of up to 500GPa/s (˜0.16s-1 for a metal). Our approach adapts electromechanical piezoelectric actuators to a conventional diamond anvil cell design, which enables precise specification and control of a time-dependent applied load/pressure. Existing DAC instrumentation and experimental techniques are easily adapted to the dDAC to measure the properties of a sample under the varying load/pressure conditions. This capability addresses the sparsely studied regime of dynamic phenomena between static research (diamond anvil cells and large volume presses) and dynamic shock-driven experiments (gas guns, explosive, and laser shock). We present an overview of a variety of experimental measurements that can be made with this device.

Reduction of air pollutant concentrations in an indoor ice-skating rink

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

Lee, K.; Yanagisawa, Yukio; Spengler, J.D.

1994-01-01

High carbon monoxide and nitrogen dioxide concentrations were measured in an indoor ice-skating rink with fuel-powered ice-resurfacing equipment. In 22% to 33% of the measurements over 90-min segments, CO concentrations exceeded 20 [mu]L/L as a 90-min average in the absence of rink ventilation. Average NO[sub 2] concentrations over 14 h were higher than 600 nL/L. Reduction of air pollutant concentrations in the ice-skating rink is necessary to prevent air-pollutant-exposure-related health incidents. Various methods for reducing air pollutants in an ice-skating rink were evaluated by simultaneously measuring CO and NO[sub 2] concentrations. Single pollution reduction attempts, such as extension of themore » exhaust pipe, reduction in the number of resurfacer operations, or use of an air recirculation system, did not significantly reduce air pollutant concentrations in the rink. Full operation of the mechanical ventilation system combined with reduced resurfacer operation was required to keep the air pollutant levels in the skating rink below the recommended guidelines. This investigation showed that management of clean air quality in an ice-skating rink is practically difficult as long as fuel-powered resurfacing equipment is used. 16 refs., 3 figs., 5 tabs.« less

Determination of beryllium concentrations in UK ambient air

NASA Astrophysics Data System (ADS)

Goddard, Sharon L.; Brown, Richard J. C.; Ghatora, Baljit K.

2016-12-01

Air quality monitoring of ambient air is essential to minimise the exposure of the general population to toxic substances such as heavy metals, and thus the health risks associated with them. In the UK, ambient air is already monitored under the UK Heavy Metals Monitoring Network for a number of heavy metals, including nickel (Ni), arsenic (As), cadmium (Cd) and lead (Pb) to ensure compliance with legislative limits. However, the UK Expert Panel on Air Quality Standards (EPAQS) has highlighted a need to limit concentrations of beryllium (Be) in air, which is not currently monitored, because of its toxicity. The aim of this work was to analyse airborne particulate matter (PM) sampled onto filter papers from the UK Heavy Metals Monitoring Network for quantitative, trace level beryllium determination and compare the results to the guideline concentration specified by EPAQS. Samples were prepared by microwave acid digestion in a matrix of 2% sulphuric acid and 14% nitric acid, verified by the use of Certified Reference Materials (CRMs). The digested samples were then analysed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The filters from the UK Heavy Metals Monitoring Network were tested using this procedure and the average beryllium concentration across the network for the duration of the study period was 7.87 pg m-3. The highest site average concentration was 32.0 pg m-3 at Scunthorpe Low Santon, which is significantly lower than levels that are thought to cause harm. However the highest levels were observed at sites monitoring industrial point sources, indicating that beryllium is being used and emitted, albeit at very low levels, from these point sources. Comparison with other metals concentrations and data from the UK National Atmospheric Emissions Inventory suggests that current emissions of beryllium may be significantly overestimated.

The architecture design of a 2mW 18-bit high speed weight voltage type DAC based on dual weight resistance chain

NASA Astrophysics Data System (ADS)

Qixing, Chen; Qiyu, Luo

2013-03-01

At present, the architecture of a digital-to-analog converter (DAC) in essence is based on the weight current, and the average value of its D/A signal current increases in geometric series according to its digital signal bits increase, which is 2n-1 times of its least weight current. But for a dual weight resistance chain type DAC, by using the weight voltage manner to D/A conversion, the D/A signal current is fixed to chain current Icha; it is only 1/2n-1 order of magnitude of the average signal current value of the weight current type DAC. Its principle is: n pairs dual weight resistances form a resistance chain, which ensures the constancy of the chain current; if digital signals control the total weight resistance from the output point to the zero potential point, that could directly control the total weight voltage of the output point, so that the digital signals directly turn into a sum of the weight voltage signals; thus the following goals are realized: (1) the total current is less than 200 μA (2) the total power consumption is less than 2 mW; (3) an 18-bit conversion can be realized by adopting a multi-grade structure; (4) the chip area is one order of magnitude smaller than the subsection current-steering type DAC; (5) the error depends only on the error of the unit resistance, so it is smaller than the error of the subsection current-steering type DAC; (6) the conversion time is only one action time of switch on or off, so its speed is not lower than the present DAC.

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

Deletion and overexpression studies on DacB2, a putative low molecular mass penicillin binding protein from Mycobacterium tuberculosis H(37)Rv.

PubMed

Bourai, Neema; Jacobs, William R; Narayanan, Sujatha

2012-02-01

Mycobacterium tuberculosis genome encodes several high and low molecular mass penicillin binding proteins. One such low molecular mass protein is DacB2 encoded by open reading frame Rv2911 of M. tuberculosis which is predicted to play a role in peptidoglycan synthesis. In this study we have tried to gain an insight into the role of this accessory cell division protein in mycobacterial physiology by performing overexpression and deletion studies. The overproduction of DacB2 in non-pathogenic, fast growing mycobacterium Mycobacterium smegmatis mc(2)155 resulted in reduced growth, an altered colony morphology, a defect in sliding motility and biofilm formation. A point mutant of DacB2 was made wherein the active site serine residue was mutated to cysteine to abolish the penicillin binding function of protein. The overexpression of mutant protein showed similar results indicating that the effects produced were independent of protein's penicillin binding function. The gene encoding DacB2 was deleted in M. tuberculosis by specialized transduction method. The deletion mutant showed reduced growth in Sauton's medium under acidic and low oxygen availability. The in vitro infection studies with THP-1 cells showed increased intracellular survival of dacB2 mutant compared to parent and complemented strains. The colony morphology and antibiotic sensitivity of mutant and wild-type strains were similar. Copyright © 2011 Elsevier Ltd. All rights reserved.

Distribution automation and control support; Analysis and interpretation of DAC working group results for use in project planning

NASA Technical Reports Server (NTRS)

Klock, P.; Evans, D.

1979-01-01

The Executive Summary and Proceedings of the Working Group Meeting was analyzed to identify specific projects appropriate for Distribution Automation and Control DAC RD&D. Specific projects that should be undertaken in the DAC RD&D program were recommended. The projects are presented under broad categories of work selected based on ESC's interpretation of the results of the Working Group Meeting. Some of the projects are noted as utility industry projects. The ESC recommendations regarding program management are presented. Utility versus Government management responsibilities are noted.

SciDAC Center for Gyrokinetic Particle Simulation of Turbulent Transport in Burning Plasmas

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

Lin, Zhihong

2013-12-18

During the first year of the SciDAC gyrokinetic particle simulation (GPS) project, the GPS team (Zhihong Lin, Liu Chen, Yasutaro Nishimura, and Igor Holod) at the University of California, Irvine (UCI) studied the tokamak electron transport driven by electron temperature gradient (ETG) turbulence, and by trapped electron mode (TEM) turbulence and ion temperature gradient (ITG) turbulence with kinetic electron effects, extended our studies of ITG turbulence spreading to core-edge coupling. We have developed and optimized an elliptic solver using finite element method (FEM), which enables the implementation of advanced kinetic electron models (split-weight scheme and hybrid model) in the SciDACmore » GPS production code GTC. The GTC code has been ported and optimized on both scalar and vector parallel computer architectures, and is being transformed into objected-oriented style to facilitate collaborative code development. During this period, the UCI team members presented 11 invited talks at major national and international conferences, published 22 papers in peer-reviewed journals and 10 papers in conference proceedings. The UCI hosted the annual SciDAC Workshop on Plasma Turbulence sponsored by the GPS Center, 2005-2007. The workshop was attended by about fifties US and foreign researchers and financially sponsored several gradual students from MIT, Princeton University, Germany, Switzerland, and Finland. A new SciDAC postdoc, Igor Holod, has arrived at UCI to initiate global particle simulation of magnetohydrodynamics turbulence driven by energetic particle modes. The PI, Z. Lin, has been promoted to the Associate Professor with tenure at UCI.« less

SciDAC-Data, A Project to Enabling Data Driven Modeling of Exascale Computing

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

Mubarak, M.; Ding, P.; Aliaga, L.

The SciDAC-Data project is a DOE funded initiative to analyze and exploit two decades of information and analytics that have been collected by the Fermilab Data Center on the organization, movement, and consumption of High Energy Physics data. The project will analyze the analysis patterns and data organization that have been used by the NOvA, MicroBooNE, MINERvA and other experiments, to develop realistic models of HEP analysis workflows and data processing. The SciDAC-Data project aims to provide both realistic input vectors and corresponding output data that can be used to optimize and validate simulations of HEP analysis. These simulations aremore » designed to address questions of data handling, cache optimization and workflow structures that are the prerequisites for modern HEP analysis chains to be mapped and optimized to run on the next generation of leadership class exascale computing facilities. We will address the use of the SciDAC-Data distributions acquired from Fermilab Data Center’s analysis workflows and corresponding to around 71,000 HEP jobs, as the input to detailed queuing simulations that model the expected data consumption and caching behaviors of the work running in HPC environments. In particular we describe in detail how the Sequential Access via Metadata (SAM) data handling system in combination with the dCache/Enstore based data archive facilities have been analyzed to develop the radically different models of the analysis of HEP data. We present how the simulation may be used to analyze the impact of design choices in archive facilities.« less

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

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 28 2013-07-01 2013-07-01 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 CAS...

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

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 27 2014-07-01 2014-07-01 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 CAS...

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

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 27 2011-07-01 2011-07-01 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 CAS...

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 CAS...

The Air Force concentrating photovoltaic array program

NASA Technical Reports Server (NTRS)

Geis, Jack W.

1987-01-01

A summary is given of Air Force solar concentrator projects beginning with the Rockwell International study program in 1977. The Satellite Materials Hardening Programs (SMATH) explored and developed techniques for hardening planar solar cell array power systems to the combined nuclear and laser radiation threat environments. A portion of program dollars was devoted to developing a preliminary design for a hardened solar concentrator. The results of the Survivable Concentrating Photovoltaic Array (SCOPA) program, and the design, fabrication and flight qualification of a hardened concentrator panel are discussed.

Diamond anvils with a round table designed for high pressure experiments in DAC

NASA Astrophysics Data System (ADS)

Dubrovinsky, Leonid; Koemets, Egor; Bykov, Maxim; Bykova, Elena; Aprilis, Georgios; Pakhomova, Anna; Glazyrin, Konstantin; Laskin, Alexander; Prakapenka, Vitali B.; Greenberg, Eran; Dubrovinskaia, Natalia

2017-10-01

Here, we present new Diamond Anvils with a Round Table (DART-anvils) designed for applications in the diamond anvil cell (DAC) technique. The main features of the new DART-anvil design are a spherical shape of both the crown and the table of a diamond and the position of the centre of the culet exactly in the centre of the sphere. The performance of DART-anvils was tested in a number of high pressure high-temperature experiments at different synchrotron beamlines. These experiments demonstrated a number of advantages, which are unavailable with any of the hitherto known anvil designs. Use of DART-anvils enables to realise in situ single-crystal X-ray diffraction experiments with laser heating using stationary laser-heating setups; eliminating flat-plate design of conventional anvils, DART-anvils make the cell alignment easier; working as solid immersion lenses, they provide additional magnification of the sample in a DAC and improve the image resolution.

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...

Experiments of the Essential Amino Acids at high temperature and high pressure using DAC

NASA Astrophysics Data System (ADS)

Kubo, K.; Okamoto, K.

2017-12-01

Amino acids are organic compounds that form the fundamental part of life. Proteins are formed by peptide binding and polymerization of amino acids. Amino acids are polymerized in the ridge hydrothermal field, formed proteins, and might be evolved into life. Experimental studies on the polymerization of amino acids in hydrothermal environments have been conducted. However, they were hydrothermal experiments and after the experiments. All run products (amid-acids) were observed at ambient condition. Few in-situ observations of amino acids were done in experiments in hydrothermal condition. In order to perform in-situ observation of the polymerization of amino acids, we have conducted the DAC experiments. Amino acids were filled in the DAC, pressures were applied, then heated to high temperature with Raman analysis. In preliminary experiment using glycine, polymerization forming diglycine, were completed. Investigation amino acids polymerization under hydrothermal condition would shed light for new view of early life science.

Bioassay vs. Air Sampling: Practical Guidance and Experience at Hanford

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

Carbaugh, Eugene H.; Carlson, Eric W.; Hill, Robin L.

2004-02-08

The Hanford Site has implemented a policy to guide in determining whether air sampling data or special fecal bioassay data are more appropriate for determining doses of record for low-level plutonium exposures. The basis for the policy and four years of experience in comparing DAC-hours exposure with bioassay-based dosimetry is discussed.

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...

High-speed ADC and DAC modules with fibre optic interconnections for telecom satellites

NASA Astrophysics Data System (ADS)

Heikkinen, Veli; Juntunen, Eveliina; Karppinen, Mikko; Kautio, Kari; Ollila, Jyrki; Sitomaniemi, Aila; Tanskanen, Antti; Casey, Rory; Scott, Shane; Gachon, Hélène; Sotom, Michel; Venet, Norbert; Toivonen, Jaakko; Tuominen, Taisto; Karafolas, Nikos

2017-11-01

The flexibility required for future telecom payloads calls for the introduction of more and more digital processing capabilities. Aggregate data throughputs of several Tbps will have to be handled onboard, thus creating the need for effective, ADCDSP and DACDSP highspeed links. ADC and DAC modules with optical interconnections is an attractive option as it can solve easily the transmission and routing of the expected huge amount of data. This technique will enable to increase the bandwidth and/or the number of beams/channels to be treated, or to support advanced digital processing architectures including beam forming. We realised electrooptic ADC and DAC modules containing an 8 bit, 2 GSa/s A/D converter and a 12 bit, 2 GSa/s D/A converter. The 4channel parallel fibre optic link employs 850nm VCSELs and GaAs PIN photodiodes coupled to 50/125μm fibre ribbon cable. ADCDSP and DSPDAC links both have an aggregate data rate of 25 Gbps. The paper presents the current status of this development.

Low concentrations of persistent organic pollutants (POPs) in air at Cape Verde.

PubMed

Nøst, Therese Haugdahl; Halse, Anne Karine; Schlabach, Martin; Bäcklund, Are; Eckhardt, Sabine; Breivik, Knut

2018-01-15

Ambient air is a core medium for monitoring of persistent organic pollutants (POPs) under the Stockholm Convention and is used in studies of global transports of POPs and their atmospheric sources and source regions. Still, data based on active air sampling remain scarce in many regions. The primary objectives of this study were to (i) monitor concentrations of selected POPs in air outside West Africa, and (ii) to evaluate potential atmospheric processes and source regions affecting measured concentrations. For this purpose, an active high-volume air sampler was installed on the Cape Verde Atmospheric Observatory at Cape Verde outside the coast of West Africa. Sampling commenced in May 2012 and 43 samples (24h sampling) were collected until June 2013. The samples were analyzed for selected polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), hexachlorobenzene (HCB) and chlordanes. The concentrations of these POPs at Cape Verde were generally low and comparable to remote sites in the Arctic for several compounds. Seasonal trends varied between compounds and concentrations exhibited strong temperature dependence for chlordanes. Our results indicate net volatilization from the Atlantic Ocean north of Cape Verde as sources of these POPs. Air mass back trajectories demonstrated that air masses measured at Cape Verde were generally transported from the Atlantic Ocean or the North African continent. Overall, the low concentrations in air at Cape Verde were likely explained by absence of major emissions in areas from which the air masses originated combined with depletion during long-range atmospheric transport due to enhanced degradation under tropical conditions (high temperatures and concentrations of hydroxyl radicals). Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

Direct Air Capture of CO2 - an Overview of Carbon Engineering's Technology and Pilot Plant Development

NASA Astrophysics Data System (ADS)

Holmes, G.; Corless, A.

2014-12-01

At Carbon Engineering, we are developing and commercializing technology to scrub CO2 directly from atmospheric air at industrial scale. By providing atmospheric CO2 for use in fuel production, we can enable production of transportation fuels with ultra-low carbon intensities, which command price premiums in the growing set of constrained fuels markets such as California's LCFS. We are a Calgary based startup founded in 2009 with 10 employees, and we are considered a global leader in the direct air capture (DAC) field. We will review CE's DAC technology, based on a wet-scrubbing "air contactor" which absorbs CO2 into aqueous solution, and a chemical looping "regeneration" component, which liberates pure CO2 from this aqueous solution while re-making the original absorption chemical. CE's DAC tecnology exports purified atmospheric CO2, combined with the combustion CO2 from plant energy usage, as the end product. We will also discuss CE's 2014-2015 end-to-end Pilot Demonstration Unit. This is a $7M technology demonstration plant that CE is building with the help of key industrial partners and equipment vendors. Vendor design and engineering requirements have been used to specify the pilot air contactor, pellet reactor, calciner, and slaker modules, as well as auxiliary systems. These modules will be run for several months to obtain the engineering and performance data needed for subsequent commercial plant design, as well as to test the residual integration risks associated with CE's process. By the time of the AGU conference, the pilot is expected to be in late stages of fabrication or early stages of site installation.

The effect of environmental parameters to dust concentration in air-conditioned space

NASA Astrophysics Data System (ADS)

Ismail, A. M. M.; Manssor, N. A. S.; Nalisa, A.; Yahaya, N.

2017-08-01

Malaysia has a wet and hot climate, therefore most of the spaces are air conditioned. The environment might affect dust concentration inside a space and affect the indoor air quality (IAQ). The main objective of this study is to study the dust concentration collected inside enclosed air-conditioned space. The measurement was done physically at four selected offices and two classrooms using a number of equipment to measure the dust concentration and environmental parameters which are temperature and relative air humidity. It was found that the highest dust concentration produced in office (temperature of 24.7°C, relative humidity of 66.5%) is 0.075 mg/m3, as compared to classroom, the highest dust concentration produced is 0.060 mg/m3 office (temperature of 25.9°C, relative humidity of 64.0%). However, both measurements show that value still within the safety level set by DOSH Malaysia (2005-2010) and ASHRAE 62.2 2016. The office contained higher dust concentration compared to classroom because of frequent movement transpires daily due to the functional of the offices.

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.

Predictors of Indoor Air Concentrations in Smoking and Non-Smoking Residences

PubMed Central

Héroux, Marie-Eve; Clark, Nina; Van Ryswyk, Keith; Mallick, Ranjeeta; Gilbert, Nicolas L.; Harrison, Ian; Rispler, Kathleen; Wang, Daniel; Anastassopoulos, Angelos; Guay, Mireille; MacNeill, Morgan; Wheeler, Amanda J.

2010-01-01

Indoor concentrations of air pollutants (benzene, toluene, formaldehyde, acetaldehyde, acrolein, nitrogen dioxide, particulate matter, elemental carbon and ozone) were measured in residences in Regina, Saskatchewan, Canada. Data were collected in 106 homes in winter and 111 homes in summer of 2007, with 71 homes participating in both seasons. In addition, data for relative humidity, temperature, air exchange rates, housing characteristics and occupants’ activities during sampling were collected. Multiple linear regression analysis was used to construct season-specific models for the air pollutants. Where smoking was a major contributor to indoor concentrations, separate models were constructed for all homes and for those homes with no cigarette smoke exposure. The housing characteristics and occupants’ activities investigated in this study explained between 11% and 53% of the variability in indoor air pollutant concentrations, with ventilation, age of home and attached garage being important predictors for many pollutants. PMID:20948949

Effect of compression rate on ice VI crystal growth using dDAC

NASA Astrophysics Data System (ADS)

Lee, Yun-Hee; Kim, Yong-Jae; Lee, Sooheyong; Cho, Yong Chan; Lee, Geun Woo; Frontier in Extreme Physics Team

It is well known that static and dynamic pressure give different results in many aspects. Understanding of crystal growth under such different pressure condition is one of the crucial issues for the formation of materials in the earth and planets. To figure out the crystal growth under the different pressure condition, we should control compression rate from static to dynamic pressurization. Here, we use a dynamic diamond anvil cell (dDAC) technique to study the effect of compression rate of ice VI crystal growth. Using dDAC with high speed camera, we monitored growth of a single crystal ice VI. A rounded ice crystal with rough surface was selected in the phase boundary of water and ice VI and then, its repetitive growth and melting has been carried out by dynamic operation of the pressure cell. The roughened crystal showed interesting growth transition with compression rate from three dimensional to two dimensional growth as well as faceting process. We will discuss possible mechanism of the growth change by compression rate with diffusion mechanism of water. This research was supported by the Converging Research Center Program through the Ministry of Science, ICT and Future Planning, Korea (NRF-2014M1A7A1A01030128).

Relationship between acetaldehyde concentration in mouth air and tongue coating volume.

PubMed

Yokoi, Aya; Maruyama, Takayuki; Yamanaka, Reiko; Ekuni, Daisuke; Tomofuji, Takaaki; Kashiwazaki, Haruhiko; Yamazaki, Yutaka; Morita, Manabu

2015-01-01

Acetaldehyde is the first metabolite of ethanol and is produced in the epithelium by mucosal ALDH, while higher levels are derived from microbial oxidation of ethanol by oral microflora such as Candida species. However, it is uncertain whether acetaldehyde concentration in human breath is related to oral condition or local production of acetaldehyde by oral microflora. The aim of this pilot study was to investigate the relationship between physiological acetaldehyde concentration and oral condition in healthy volunteers. Sixty-five volunteers (51 males and 14 females, aged from 20 to 87 years old) participated in the present study. Acetaldehyde concentration in mouth air was measured using a portable monitor. Oral examination, detection of oral Candida species and assessment of alcohol sensitivity were performed. Acetaldehyde concentration [median (25%, 75%)] in mouth air was 170.7 (73.5, 306.3) ppb. Acetaldehyde concentration in participants with a tongue coating status score of 3 was significantly higher than in those with a score of 1 (p<0.017). After removing tongue coating, acetaldehyde concentration decreased significantly (p<0.05). Acetaldehyde concentration was not correlated with other clinical parameters, presence of Candida species, smoking status or alcohol sensitivity. Physiological acetaldehyde concentration in mouth air was associated with tongue coating volume.

Relationship between acetaldehyde concentration in mouth air and tongue coating volume

PubMed Central

YOKOI, Aya; MARUYAMA, Takayuki; YAMANAKA, Reiko; EKUNI, Daisuke; TOMOFUJI, Takaaki; KASHIWAZAKI, Haruhiko; YAMAZAKI, Yutaka; MORITA, Manabu

2015-01-01

Objective Acetaldehyde is the first metabolite of ethanol and is produced in the epithelium by mucosal ALDH, while higher levels are derived from microbial oxidation of ethanol by oral microflora such as Candida species. However, it is uncertain whether acetaldehyde concentration in human breath is related to oral condition or local production of acetaldehyde by oral microflora. The aim of this pilot study was to investigate the relationship between physiological acetaldehyde concentration and oral condition in healthy volunteers. Material and Methods Sixty-five volunteers (51 males and 14 females, aged from 20 to 87 years old) participated in the present study. Acetaldehyde concentration in mouth air was measured using a portable monitor. Oral examination, detection of oral Candida species and assessment of alcohol sensitivity were performed. Results Acetaldehyde concentration [median (25%, 75%)] in mouth air was 170.7 (73.5, 306.3) ppb. Acetaldehyde concentration in participants with a tongue coating status score of 3 was significantly higher than in those with a score of 1 (p<0.017). After removing tongue coating, acetaldehyde concentration decreased significantly (p<0.05). Acetaldehyde concentration was not correlated with other clinical parameters, presence of Candida species, smoking status or alcohol sensitivity. Conclusion Physiological acetaldehyde concentration in mouth air was associated with tongue coating volume. PMID:25760268

10 CFR 835.209 - Concentrations of radioactive material in air.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Section 835.209 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Standards for Internal and 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 bioassay...

Treatment of reverse osmosis (RO) concentrate by the combined Fe/Cu/air and Fenton process (1stFe/Cu/air-Fenton-2ndFe/Cu/air).

PubMed

Ren, Yi; Yuan, Yue; Lai, Bo; Zhou, Yuexi; Wang, Juling

2016-01-25

To decompose or transform the toxic and refractory reverse osmosis (RO) concentrate and improve the biodegradability, 1stFe/Cu/air-Fenton-2ndFe/Cu/air were developed to treat RO concentrate obtained from an amino acid production plant in northern China. First, their operating conditions were optimized thoroughly. Furthermore, 5 control experiments were setup to confirm the superiority of 1stFe/Cu/air-Fenton-2ndFe/Cu/air and synergistic reaction between Fe/Cu/air and Fenton. The results suggest that the developed method could obtain high COD removal (65.1%) and BOD5/COD ratio (0.26) due to the synergistic reaction between Fe/Cu/air and Fenton. Under the optimal conditions, the influent and effluent of 1stFe/Cu/air-Fenton-2ndFe/Cu/air and 5 control experiments were analyzed by using UV, FTIR, EEM and LC, which confirm the superiority of 1stFe/Cu/air-Fenton-2ndFe/Cu/air. Therefore, the developed method in this study is a promising process for treatment of RO concentrate. Copyright © 2015 Elsevier B.V. All rights reserved.

Iowa State University – Final Report for SciDAC3/NUCLEI

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

Vary, James P

The Iowa State University (ISU) contributions to the NUCLEI project are focused on developing, implementing and running an efficient and scalable configuration interaction code (Many-Fermion Dynamics – nuclear or MFDn) for leadership class supercomputers addressing forefront research problems in low-energy nuclear physics. We investigate nuclear structure and reactions with realistic nucleon-nucleon (NN) and three-nucleon (3N) interactions. We select a few highlights from our work that has produced a total of more than 82 refereed publications and more than 109 invited talks under SciDAC3/NUCLEI.

10 CFR Appendix C to Part 835 - Derived Air Concentration (DAC) for Workers From External Exposure During Immersion in a Cloud of...

Code of Federal Regulations, 2012 CFR

2012-01-01

... Exposure During Immersion in a Cloud of Airborne Radioactive Material C Appendix C to Part 835 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Pt. 835, App. C Appendix C to Part 835—Derived Air... Material a. The data presented in appendix C are to be used for controlling occupational exposures in...

10 CFR Appendix C to Part 835 - Derived Air Concentration (DAC) for Workers From External Exposure During Immersion in a Cloud of...

Code of Federal Regulations, 2011 CFR

2011-01-01

... Exposure During Immersion in a Cloud of Airborne Radioactive Material C Appendix C to Part 835 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Pt. 835, App. C Appendix C to Part 835—Derived Air... Material a. The data presented in appendix C are to be used for controlling occupational exposures in...

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

System Design Description for the SY-101 Hydrogen Mitigation Test Project Data Acquisition and Control System (DACS-1)

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

ERMI, A.M.

2000-01-24

This document describes the hardware and software of the computer subsystems for the Data Acquisition and Control System (DACS) used in mitigation tests conducted on waste tank 241-SY-101 at the Hanford Nuclear Reservation.

Characterization of Mutants Deficient in the l,d-Carboxypeptidase (DacB) and WalRK (VicRK) Regulon, Involved in Peptidoglycan Maturation of Streptococcus pneumoniae Serotype 2 Strain D39▿†

PubMed Central

Barendt, Skye M.; Sham, Lok-To; Winkler, Malcolm E.

2011-01-01

Peptidoglycan (PG) hydrolases play critical roles in the remodeling of bacterial cell walls during division. PG hydrolases have been studied extensively in several bacillus species, such as Escherichia coli and Bacillus subtilis, but remain relatively uncharacterized in ovococcus species, such as Streptococcus pneumoniae (pneumococcus). In this work, we identified genes that encode proteins with putative PG hydrolytic domains in the genome of S. pneumoniae strain D39. Knockout mutations in these genes were constructed, and the resulting mutants were characterized in comparison with the parent strain for growth, cell morphology, PG peptide incorporation, and in some cases, PG peptide composition. In addition, we characterized deletion mutations in nonessential genes of unknown function in the WalRKSpn two-component system regulon, which also contains the essential pcsB cell division gene. Several mutants did not show overt phenotypes, which is perhaps indicative of redundancy. In contrast, two new mutants showed distinct defects in PG biosynthesis. One mutation was in a gene designated dacB (spd_0549), which we showed encodes an l,d-carboxypeptidase involved in PG maturation. Notably, dacB mutants, similar to dacA (d,d-carboxypeptidase) mutants, exhibited defects in cell shape and septation, consistent with the idea that the availability of PG peptide precursors is important for proper PG biosynthesis. Epistasis analysis indicated that DacA functions before DacB in d-Ala removal, and immunofluorescence microscopy showed that DacA and DacB are located over the entire surface of pneumococcal cells. The other mutation was in WalRKSpn regulon gene spd_0703, which encodes a putative membrane protein that may function as a type of conserved streptococcal shape, elongation, division, and sporulation (SEDS) protein. PMID:21378199

The Effects of Scavenging on Waste Methoxyflurane Concentrations in Veterinary Operating Room Air

DTIC Science & Technology

1981-01-01

Afl-AO5 572 AIR FORCE OCCUPATIONAL AND ENVIRONMENTAL H4EALTH LAS -ETC F/S 6120 TIE EFFECTS OF SCAVENGING ON WASTE METHOXYFLURANE CONCENTRATIOH-ETC...REPRINT The Effects of Scavenging on Waste Methoxyflurane Concentrations in Veterinary Operating Room Air Approved for public release; distribution...Waste Methoxyflurane Fnal y t Concentrations ir Veterinary Operating Room Air, 6.PROMN _6._PERFORMIN oIG. REPORT NUMBER 7. AUTOR~s)B. CONTRACT OR GRANT

45 CFR 1705.3 - Procedures for requests pertaining to individual records in the D/AC File.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 45 Public Welfare 4 2011-10-01 2011-10-01 false Procedures for requests pertaining to individual records in the D/AC File. 1705.3 Section 1705.3 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL COMMISSION ON LIBRARIES AND INFORMATION SCIENCE PRIVACY REGULATIONS § 1705.3 Procedures...

45 CFR 1705.3 - Procedures for requests pertaining to individual records in the D/AC File.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 45 Public Welfare 4 2010-10-01 2010-10-01 false Procedures for requests pertaining to individual records in the D/AC File. 1705.3 Section 1705.3 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL COMMISSION ON LIBRARIES AND INFORMATION SCIENCE PRIVACY REGULATIONS § 1705.3 Procedures...

45 CFR 1705.3 - Procedures for requests pertaining to individual records in the D/AC File.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 45 Public Welfare 4 2012-10-01 2012-10-01 false Procedures for requests pertaining to individual records in the D/AC File. 1705.3 Section 1705.3 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL COMMISSION ON LIBRARIES AND INFORMATION SCIENCE PRIVACY REGULATIONS § 1705.3 Procedures...

45 CFR 1705.3 - Procedures for requests pertaining to individual records in the D/AC File.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 45 Public Welfare 4 2013-10-01 2013-10-01 false Procedures for requests pertaining to individual records in the D/AC File. 1705.3 Section 1705.3 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL COMMISSION ON LIBRARIES AND INFORMATION SCIENCE PRIVACY REGULATIONS § 1705.3 Procedures...

45 CFR 1705.3 - Procedures for requests pertaining to individual records in the D/AC File.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 45 Public Welfare 4 2014-10-01 2014-10-01 false Procedures for requests pertaining to individual records in the D/AC File. 1705.3 Section 1705.3 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL COMMISSION ON LIBRARIES AND INFORMATION SCIENCE PRIVACY REGULATIONS § 1705.3 Procedures...

National Computational Infrastructure for Lattice Gauge Theory SciDAC-2 Closeout Report Indiana University Component

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

Gottlieb, Steven Arthur; DeTar, Carleton; Tousaint, Doug

This is the closeout report for the Indiana University portion of the National Computational Infrastructure for Lattice Gauge Theory project supported by the United States Department of Energy under the SciDAC program. It includes information about activities at Indian University, the University of Arizona, and the University of Utah, as those three universities coordinated their activities.

Eicosanoids modulate hyperpnea-induced late phase airway obstruction and hyperreactivity in dogs.

PubMed

Davis, Michael S; McCulloch, Sharron; Myers, Teresa; Freed, Arthur N

2002-01-01

A canine model of exercise-induced asthma was used to test the hypothesis that the development of a late phase response to hyperventilation depends on the acute production of pro-inflammatory mediators. Peripheral airway resistance, reactivity to hypocapnia and aerosol histamine, and bronchoalveolar lavage fluid (BALF) cell and eicosanoid content were measured in dogs approximately 5 h after dry air challenge (DAC). DAC resulted in late phase obstruction, hyperreactivity to histamine, and neutrophilic inflammation. Both cyclooxygenase and lipoxygenase inhibitors administered in separate experiments attenuated the late phase airway obstruction and hyperreactivity to histamine. Neither drug affected the late phase inflammation nor the concentrations of eicosanoids in the BALF obtained 5 h after DAC. This study confirms that hyperventilation of peripheral airways with unconditioned air causes late phase neutrophilia, airway obstruction, and hyperreactivity. The late phase changes in airway mechanics are related to the hyperventilation-induced release of both prostaglandins and leukotrienes, and appear to be independent of the late phase infiltration of inflammatory cells.

Historical occupational trichloroethylene air concentrations based on inspection measurements from Shanghai, China.

PubMed

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

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. 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. 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 = 150-190 mg 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 11 mg m(-3) in 'other metal products/repair' industries to 390 mg m(-3) in 'ships/aircrafts' industries. 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. Published by Oxford University Press on behalf of the British Occupational Hygiene Society 2014.

Contributions to the NUCLEI SciDAC-3 Project

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

Bogner, Scott; Nazarewicz, Witek

This is the Final Report for Michigan State University for the NUCLEI SciDAC-3 project. The NUCLEI project, as defined by the scope of work, has developed, implemented and run codes for large-scale computations of many topics in low-energy nuclear physics. Physics studied included the properties of nuclei and nuclear decays, nuclear structure and reactions, and the properties of nuclear matter. The computational techniques used included Configuration Interaction, Coupled Cluster, and Density Functional methods. The research program emphasized areas of high interest to current and possible future DOE nuclear physics facilities, including ATLAS at ANL and FRIB at MSU (nuclear structuremore » and reactions, and nuclear astrophysics), TJNAF (neutron distributions in nuclei, few body systems, and electroweak processes), NIF (thermonuclear reactions), MAJORANA and FNPB (neutrinoless double-beta decay and physics beyond the Standard Model), and LANSCE (fission studies).« less

Performance Engineering Research Institute SciDAC-2 Enabling Technologies Institute Final Report

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

Hall, Mary

2014-09-19

Enhancing the performance of SciDAC applications on petascale systems has high priority within DOE SC. As we look to the future, achieving expected levels of performance on high-end com-puting (HEC) systems is growing ever more challenging due to enormous scale, increasing archi-tectural complexity, and increasing application complexity. To address these challenges, PERI has implemented a unified, tripartite research plan encompassing: (1) performance modeling and prediction; (2) automatic performance tuning; and (3) performance engineering of high profile applications. The PERI performance modeling and prediction activity is developing and refining performance models, significantly reducing the cost of collecting the data upon whichmore » the models are based, and increasing model fidelity, speed and generality. Our primary research activity is automatic tuning (autotuning) of scientific software. This activity is spurred by the strong user preference for automatic tools and is based on previous successful activities such as ATLAS, which has automatically tuned components of the LAPACK linear algebra library, and other re-cent work on autotuning domain-specific libraries. Our third major component is application en-gagement, to which we are devoting approximately 30% of our effort to work directly with Sci-DAC-2 applications. This last activity not only helps DOE scientists meet their near-term per-formance goals, but also helps keep PERI research focused on the real challenges facing DOE computational scientists as they enter the Petascale Era.« less

Influence of relative humidity on VOC concentrations in indoor air.

PubMed

Markowicz, Pawel; Larsson, Lennart

2015-04-01

Volatile organic compounds (VOCs) may be emitted from surfaces indoors leading to compromised air quality. This study scrutinized the influence of relative humidity (RH) on VOC concentrations in a building that had been subjected to water damage. While air samplings in a damp room at low RH (21-22%) only revealed minor amounts of 2-ethylhexanol (3 μg/m(3)) and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB, 8 μg/m(3)), measurements performed after a rapid increase of RH (to 58-75%) revealed an increase in VOC concentrations which was 3-fold for 2-ethylhexanol and 2-fold for TXIB. Similar VOC emission patterns were found in laboratory analyses of moisture-affected and laboratory-contaminated building materials. This study demonstrates the importance of monitoring RH when sampling indoor air for VOCs in order to avoid misleading conclusions from the analytical results.

Air quality, primary air pollutants and ambient concentrations inventory for Romania

NASA Astrophysics Data System (ADS)

Năstase, Gabriel; Șerban, Alexandru; Năstase, Alina Florentina; Dragomir, George; Brezeanu, Alin Ionuț

2018-07-01

Air pollution is among the greatest risk factors for human health, but it also poses risks to the food security, the economy and the environment. The majority of the pollutants emitted by human activities derive from the production and use of fossil-fuel-based energy. Most energy-related emissions contain sulfur dioxide and nitrogen oxides. The principal source of sulfur dioxide originates from coal, and the main sources of nitrogen oxide emissions are power generation and use of vehicles. Other important pollutants are the inhalable coarse particles (PM10) and the fine particulate matter (PM2.5), which arises from the building sector. Over the last decade, since Romania joined the European Union on the 1st of January 2007, the use of fossil fuels has decreased dramatically, as consumers switched to either natural gas or biomass. This was as a result of the European Commission encouraging the member countries to make use of renewable sources (including biomass). To reduce the PM emissions, in April 2015 EC has extended the EcoDesign Directive to solid-fuel boilers and solid-fuel space heaters. The boilers need to generally meet certain requirements that will be introduced by 1 January 2020. In this article, we are highlighting the fluctuations in air pollution in Romania from the European WebDAB - EMAP database and trends in ambient concentrations of air pollutants using Romania's national air pollution monitoring network. Romania's Air Pollutants/Air Quality Monitoring Network consists of 142 automatic air quality monitoring stations. The results indicate that Romania's annual average mass emissions of CO decreased from 3186 Gg in 1990 to 774 in 2014 (decrease by <76%), SOx decreased from 1311 Gg-176 Gg (decrease by ∼60%), NOx decreased from 546 Gg to 218 (decrease by ∼87%), CO2 decreased from 66.226 Gg/year in 2007 to 38.916 Gg/year in 2014 (decrease by <41%).

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.

Relationships between Atmospheric Transport Regimes and PCB Concentrations in the Air at Zeppelin, Spitsbergen.

PubMed

Ubl, Sandy; Scheringer, Martin; Hungerbühler, Konrad

2017-09-05

Polychlorinated biphenyls (PCBs) are persistent hazardous chemicals that are still detected in the atmosphere and other environmental media, although their production has been banned for several decades. At the long-term monitoring site, Zeppelin at Spitsbergen, different PCB congeners have been continuously measured for more than a decade. However, it is not clear what factors determine the seasonal and interannual variability of different (lighter versus heavier) PCB congeners. To investigate the influence of atmospheric transport patterns on PCB-28 and PCB-101 concentrations at Zeppelin, we applied the Lagrangian Particle Dispersion Model FLEXPART and calculated "footprints" that indicate the potential source regions of air arriving at Zeppelin. By means of a cluster analysis, we assigned groups of similar footprints to different transport regimes and analyzed the PCB concentrations according to the transport regimes. The concentrations of both PCB congeners are affected by the different transport regimes. For PCB-101, the origin of air masses from the European continent is primarily related to high concentrations; elevated PCB-101 concentrations in winter can be explained by the high frequency of this transport regime in winter, whereas PCB-101 concentrations are low when air is arriving from the oceans. For PCB-28, in contrast, concentrations are high during summer when air is mainly arriving from the oceans but low when air is arriving from the continents. The most likely explanation of this finding is that local emissions of PCB-28 mask the effect of long-range transport and determine the concentrations measured at Zeppelin.

CONCENTRATED AMBIENT AIR PARTICLES INDUCE PULMONARY INFLAMMATION IN HEALTHY HUMAN VOLUNTEERS

EPA Science Inventory

We tested the hypothesis that exposure of healthy volunteers to concentrated ambient particles (CAPS) is associated with an influx of inflammatory cells into the lower respiratory tract. Thirty-eight volunteers were exposed to either filtered air or particles concentrated fro...

A passive air sampler for characterizing the vertical concentration profile of gaseous phase polycyclic aromatic hydrocarbons in near soil surface air.

PubMed

Zhang, Yuzhong; Deng, Shuxing; Liu, Yanan; Shen, Guofeng; Li, Xiqing; Cao, Jun; Wang, Xilong; Reid, Brian; Tao, Shu

2011-03-01

Air-soil exchange is an important process governing the fate of polycyclic aromatic hydrocarbons (PAHs). A novel passive air sampler was designed and tested for measuring the vertical concentration profile of 4 low molecular weight PAHs in gaseous phase (PAH(LMW4)) in near soil surface air. Air at various heights from 5 to 520 mm above the ground was sampled by polyurethane foam disks held in down-faced cartridges. The samplers were tested at three sites: A: an extremely contaminated site, B: a site near A, and C: a background site on a university campus. Vertical concentration gradients were revealed for PAH(LMW4) within a thin layer close to soil surface at the three sites. PAH concentrations either decreased (Site A) or increased (Sites B and C) with height, suggesting either deposition to or evaporation from soils. The sampler is a useful tool for investigating air-soil exchange of gaseous phase semi-volatile organic chemicals. Copyright © 2010 Elsevier Ltd. All rights reserved.

Statistical study of air pollutant concentrations via generalized gamma distribution

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

Marani, A.; Lavagnini, I.; Buttazzoni, C.

1986-11-01

This paper deals with modeling observed frequency distributions of air quality data measured in the area of Venice, Italy. The paper discusses the application of the generalized gamma distribution (ggd) which has not been commonly applied to air quality data notwithstanding the fact that it embodies most distribution models used for air quality analyses. The approach yields important simplifications for statistical analyses. A comparison among the ggd and other relevant models (standard gamma, Weibull, lognormal), carried out on daily sulfur dioxide concentrations in the area of Venice underlines the efficiency of ggd models in portraying experimental data.

Modelling and analysis of ozone concentration by artificial intelligent techniques for estimating air quality

NASA Astrophysics Data System (ADS)

Taylan, Osman

2017-02-01

High ozone concentration is an important cause of air pollution mainly due to its role in the greenhouse gas emission. Ozone is produced by photochemical processes which contain nitrogen oxides and volatile organic compounds in the lower atmospheric level. Therefore, monitoring and controlling the quality of air in the urban environment is very important due to the public health care. However, air quality prediction is a highly complex and non-linear process; usually several attributes have to be considered. Artificial intelligent (AI) techniques can be employed to monitor and evaluate the ozone concentration level. The aim of this study is to develop an Adaptive Neuro-Fuzzy inference approach (ANFIS) to determine the influence of peripheral factors on air quality and pollution which is an arising problem due to ozone level in Jeddah city. The concentration of ozone level was considered as a factor to predict the Air Quality (AQ) under the atmospheric conditions. Using Air Quality Standards of Saudi Arabia, ozone concentration level was modelled by employing certain factors such as; nitrogen oxide (NOx), atmospheric pressure, temperature, and relative humidity. Hence, an ANFIS model was developed to observe the ozone concentration level and the model performance was assessed by testing data obtained from the monitoring stations established by the General Authority of Meteorology and Environment Protection of Kingdom of Saudi Arabia. The outcomes of ANFIS model were re-assessed by fuzzy quality charts using quality specification and control limits based on US-EPA air quality standards. The results of present study show that the ANFIS model is a comprehensive approach for the estimation and assessment of ozone level and is a reliable approach to produce more genuine outcomes.

Predicting indoor pollutant concentrations, and applications to air quality management

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

Lorenzetti, David M.

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'' symptomsmore » 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.« less

[The effect of the ventilation rate on air particle and air microbe concentration in operating rooms with conventional ventilation. 1. Measurement without surgical activity].

PubMed

Kruppa, B; Rüden, H

1993-05-01

The question was if a reduction of airborne particles and bacteria in conventionally (turbulently), ventilated operating theatres in comparison to Laminar-Airflow (LAF) operating theatres does occur at high air-exchange-rates. Within the framework of energy consumption measures the influence of air-exchange-rates on airborne particle and bacteria concentrations was determined in two identical operating theatres with conventional ventilation (wall diffusor panel) at the air-exchange-rates 7.5, 10, 15 and 20/h without surgical activity. This was established by means of the statistical procedure of analysis of variance. Especially for the comparison of the air-exchange-rates 7.5 and 15/h statistical differences were found for airborne particle concentrations in supply and ambient air. Concerning airborne bacteria concentrations no differences were found among the various air-exchange-rates. Explanation of variance is quite high for non-viable particles (supply air: 37%, ambient air: 81%) but negligible for viable particles (bacteria) with values below 15%.

Dynamic adaptive chemistry for turbulent flame simulations

NASA Astrophysics Data System (ADS)

Yang, Hongtao; Ren, Zhuyin; Lu, Tianfeng; Goldin, Graham M.

2013-02-01

The use of large chemical mechanisms in flame simulations is computationally expensive due to the large number of chemical species and the wide range of chemical time scales involved. This study investigates the use of dynamic adaptive chemistry (DAC) for efficient chemistry calculations in turbulent flame simulations. DAC is achieved through the directed relation graph (DRG) method, which is invoked for each computational fluid dynamics cell/particle to obtain a small skeletal mechanism that is valid for the local thermochemical condition. Consequently, during reaction fractional steps, one needs to solve a smaller set of ordinary differential equations governing chemical kinetics. Test calculations are performed in a partially-stirred reactor (PaSR) involving both methane/air premixed and non-premixed combustion with chemistry described by the 53-species GRI-Mech 3.0 mechanism and the 129-species USC-Mech II mechanism augmented with recently updated NO x pathways, respectively. Results show that, in the DAC approach, the DRG reduction threshold effectively controls the incurred errors in the predicted temperature and species concentrations. The computational saving achieved by DAC increases with the size of chemical kinetic mechanisms. For the PaSR simulations, DAC achieves a speedup factor of up to three for GRI-Mech 3.0 and up to six for USC-Mech II in simulation time, while at the same time maintaining good accuracy in temperature and species concentration predictions.

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...

[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.

A cryogenic DAC operating down to 4.2 K

NASA Astrophysics Data System (ADS)

Rahman, M. T.; Lehmann, T.

2016-04-01

This paper presents a 10 bit CMOS current steering digital to analog converter (DAC) that operates from room temperature to as low as 4.2 K. It works as the core part of a cryogenic Silicon quantum computer controller circuit producing rapid control gate voltage pulses for quantum bits (qubits) initialization. An improved analog calibration method with a unique unit current cell design is included in the D/A converter structure to overcome the extended cryogenic nonlinear and mismatch effects. The DAC retains its 10 bit linear monotonic behavior over the wide temperature range and it drives a 50 Ω load to 516 mV with a full scale rise time of 10 ns. The differential non-linearity (DNL) of the converter is 0.35LSB while its average power consumption is 32.18 mW from a 3 V power supply. The complete converter is fabricated using a commercial 0.5 μm 1 poly 3 metal Silicon on Sapphire (SOS) CMOS process. He briefly worked as a Lecturer in the Stamford University Bangladesh prior to starting his Ph.D. in 2012 in the School of Electrical Engineering and Telecommunications, UNSW. His Ph.D. research is focused on cryogenic electronics for Quantum Computer Interface. His main research interests are in designing data converters for ultra-low temperature electronics and biomedical applications. He spent two years as a Research Fellow at the University of Edinburgh, U.K., where he worked with biologically inspired artificial neural systems. From 1997 to 2000, he was an Assistant Professor in electronics at the Technical University of Denmark, working with low-power low-noise low-voltage analog and mixed analog-digital integrated circuits. From 2001 to 2003 he was Principal Engineer with Cochlear Ltd., Australia, where he was involved in the design of the world's first fully implantable cochlear implant. Today he is Associate Professor in microelectronics at the University of New South Wales, Australia. He has authored over 100 journal papers, conference papers, book chapters

Modeling air concentration over macro roughness conditions by Artificial Intelligence techniques

NASA Astrophysics Data System (ADS)

Roshni, T.; Pagliara, S.

2018-05-01

Aeration is improved in rivers by the turbulence created in the flow over macro and intermediate roughness conditions. Macro and intermediate roughness flow conditions are generated by flows over block ramps or rock chutes. The measurements are taken in uniform flow region. Efficacy of soft computing methods in modeling hydraulic parameters are not common so far. In this study, modeling efficiencies of MPMR model and FFNN model are found for estimating the air concentration over block ramps under macro roughness conditions. The experimental data are used for training and testing phases. Potential capability of MPMR and FFNN model in estimating air concentration are proved through this study.

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.

Genetic algorithms for GNC settings and DACS design application to an asteroid Kinetic Impactor

NASA Astrophysics Data System (ADS)

Vernis, P.; Oliviero, V.

2018-06-01

This paper deals with an application of Genetic Algorithm (GA) tools in order to perform and optimize the settings phase of the Guidance, Navigation, and Control (GNC) data set for the endgame phase of a Kinetic Impactor (KI) targeting a medium-size Near Earth Object (NEO). A coupled optimization of the GNC settings and of the GC-oriented design of the Divert and Attitude Control System (DACS) is also proposed. The illustration of the developed principles is made considering the NEOShield study frame.

Risk-based containment and air monitoring criteria for work with dispersible radioactive materials.

PubMed

Veluri, Venkateswara Rao; Justus, Alan L

2013-04-01

This paper presents readily understood, technically defensible, risk-based containment and air monitoring criteria, which are developed from fundamental physical principles. The key for the development of each criterion was the use of a calculational de minimis level, in this case chosen to be 100 mrem (or 40 DAC-h). Examples are provided that demonstrate the effective use of each criterion. Comparison to other often used criteria is provided.

Evaluation of air quality zone classification methods based on ambient air concentration exposure.

PubMed

Freeman, Brian; McBean, Ed; Gharabaghi, Bahram; Thé, Jesse

2017-05-01

Air quality zones are used by regulatory authorities to implement ambient air standards in order to protect human health. Air quality measurements at discrete air monitoring stations are critical tools to determine whether an air quality zone complies with local air quality standards or is noncompliant. This study presents a novel approach for evaluation of air quality zone classification methods by breaking the concentration distribution of a pollutant measured at an air monitoring station into compliance and exceedance probability density functions (PDFs) and then using Monte Carlo analysis with the Central Limit Theorem to estimate long-term exposure. The purpose of this paper is to compare the risk associated with selecting one ambient air classification approach over another by testing the possible exposure an individual living within a zone may face. The chronic daily intake (CDI) is utilized to compare different pollutant exposures over the classification duration of 3 years between two classification methods. Historical data collected from air monitoring stations in Kuwait are used to build representative models of 1-hr NO 2 and 8-hr O 3 within a zone that meets the compliance requirements of each method. The first method, the "3 Strike" method, is a conservative approach based on a winner-take-all approach common with most compliance classification methods, while the second, the 99% Rule method, allows for more robust analyses and incorporates long-term trends. A Monte Carlo analysis is used to model the CDI for each pollutant and each method with the zone at a single station and with multiple stations. The model assumes that the zone is already in compliance with air quality standards over the 3 years under the different classification methodologies. The model shows that while the CDI of the two methods differs by 2.7% over the exposure period for the single station case, the large number of samples taken over the duration period impacts the sensitivity

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

Roles of Meteorology in Changes of Air Pollutants Concentrations in China from 2010 to 2015

NASA Astrophysics Data System (ADS)

Wang, P.; Kota, S. H.; Hu, J.; Ying, Q.; Zhang, H.

2017-12-01

Tremendous efforts have been made to control the severe air pollution in China in recent years. However, no significant improvement was observed according to annual fine particulate matter (PM2.5) concentrations and the concentrations in severe air pollution events in winter. This is partially due to the role of meteorology, which affects the emission, transport, transformation, and deposition of air pollutants. In this study, simulation of air pollutants over China was conducted for six years from 2010 to 2015 with constant anthropogenic emissions to verify the changes of air pollutants due to meteorology changes only. Model performance was validated by comparing with meteorological observations and air pollutants measures from various sources. Four different regions/cities were selected to understand the changes in wind, mixing layer height, temperature, and relative humanity at different seasons. The changes in concentrations of pollutants including PM2.5 and its chemical components and ozone were analyzed and associated with meteorological changes. This study would provide information for designing effective control strategies in different areas with the consideration of meteorological and climate changes.

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

Concentrations of Reactive Trace Gases In The Interstitial Air of Surface Snow

NASA Astrophysics Data System (ADS)

Jacobi, H.-W.; Honrath, R. E.; Peterson, M. C.; Lu, Y.; Dibb, J. E.; Arsenault, M. A.; Swanson, A. L.; Blake, N. J.; Bales, R. C.; Schrems, O.

Several measurements at Arctic and Antarctic sites have demonstrated that unexpected photochemical reactions occur in irradiated surface snow influencing the composi- tion of the boundary layer over snow-covered areas. The results of these reactions are probably most obvious in the interstitial air of the surface snow since it constitutes the interface between the surface snow and the boundary layer. Therefore, measurements of concentrations of nitrogen oxide and dioxide, nitrous acid, formaldehyde, hydro- gen peroxide, formic acid, acetic acid, and other organic compounds were performed in the interstitial air of the surface snow of the Greenland ice sheet. Concentrations were measured at variable depths between - 10 cm and - 50 cm during the summer field season in 2000 at the Summit Environmental Observatory. At shallow depths, the system NO-NO2-O3 exhibits large deviations from the calculated photostationary state. Using steady-state analyses applied to OH-HO2-CH3O2 cycling indicated the presence of high concentrations of OH and peroxy radicals in the firn air. Maximum concentrations calculated for a depth of - 10 cm are in the order of 6 105 molecules cm-3 and 1.4 * 107 molecules cm-3 for OH and HO2, respectively, although radia- tion levels at - 10 cm are reduced by approximately 50 % compared to levels above the snow surface. By far the most important OH source is the photolysis of HONO while the photolysis of ozone contributes less than 2 % to the overall production of OH in the firn air.

Parametric study of a concentric coaxial glass tube solar air collector: a theoretical approach

NASA Astrophysics Data System (ADS)

Dabra, Vishal; Yadav, Avadhesh

2017-12-01

Concentric coaxial glass tube solar air collector (CCGTSAC) is a quite innovative development in the field of solar collectors. This type of collector is specially designed to produce hot air. A mathematical model based on the energy conservation equations for small control volumes along the axial direction of concentric coaxial glass tube (CCGT) is developed in this paper. It is applied to predict the effect of thirteen different parameters on the exit air temperature rise and appeared that absorber tube size, length of CCGT, absorptivity of transparent glazing, transmissivity of transparent glazing, absorptivity of absorber coating, inlet or ambient air temperature, mass flow rate, variation of thermo-physical properties of air, wind speed, solar intensity and vacuum present between transparent glazing and absorber tube are significant parameters. Results of the model were analysed to predict the effect of key parameters on the thermal performance of a CCGTSAC for exit air temperature rise about 43.9-58.4 °C.

Parametric study of a concentric coaxial glass tube solar air collector: a theoretical approach

NASA Astrophysics Data System (ADS)

Dabra, Vishal; Yadav, Avadhesh

2018-06-01

Concentric coaxial glass tube solar air collector (CCGTSAC) is a quite innovative development in the field of solar collectors. This type of collector is specially designed to produce hot air. A mathematical model based on the energy conservation equations for small control volumes along the axial direction of concentric coaxial glass tube (CCGT) is developed in this paper. It is applied to predict the effect of thirteen different parameters on the exit air temperature rise and appeared that absorber tube size, length of CCGT, absorptivity of transparent glazing, transmissivity of transparent glazing, absorptivity of absorber coating, inlet or ambient air temperature, mass flow rate, variation of thermo-physical properties of air, wind speed, solar intensity and vacuum present between transparent glazing and absorber tube are significant parameters. Results of the model were analysed to predict the effect of key parameters on the thermal performance of a CCGTSAC for exit air temperature rise about 43.9-58.4 °C.

Time lag between the tropopause height and the levels of 7Be concentration in near surface air

NASA Astrophysics Data System (ADS)

Ioannidou, A.; Vasileiadis, A.; Melas, D.

2012-04-01

The concentration of 7Be at near surface air has been determined over 2009, a year of a deep solar minimum, in the region of Thessaloniki, Greece at 40°62' N, 22°95'E. In geomagnetic latitudes over 40° N, the elevation of the tropopause during the warm summer months and the vertical exchange of air masses within the troposphere cause greater mixture of the air masses resulting in higher concentration levels for 7Be in surface air. The positive correlation between the monthly activity concentration of 7Be and the tropopause height (0.94, p < 0.0001), and also between 7Be concentration and the temperature T (°C) (R = 0.97, p < 0.001), confirm that the increased rate of vertical transport within the troposphere, especially during warmer summer months, has as a result the descent to surface of air masses enriched in 7Be. However, the 7Be concentration levels in near surface air are not expected to respond immediately to the change of elevation of the tropopause. It was found that there's a time lag of ~ 3 days between the change in the daily surface concentrations of 7Be the change in the elevation of the tropopause.

Prediction of Air Pollutants Concentration Based on an Extreme Learning Machine: The Case of Hong Kong

PubMed Central

Zhang, Jiangshe; Ding, Weifu

2017-01-01

With the development of the economy and society all over the world, most metropolitan cities are experiencing elevated concentrations of ground-level air pollutants. It is urgent to predict and evaluate the concentration of air pollutants for some local environmental or health agencies. Feed-forward artificial neural networks have been widely used in the prediction of air pollutants concentration. However, there are some drawbacks, such as the low convergence rate and the local minimum. The extreme learning machine for single hidden layer feed-forward neural networks tends to provide good generalization performance at an extremely fast learning speed. The major sources of air pollutants in Hong Kong are mobile, stationary, and from trans-boundary sources. We propose predicting the concentration of air pollutants by the use of trained extreme learning machines based on the data obtained from eight air quality parameters in two monitoring stations, including Sham Shui Po and Tap Mun in Hong Kong for six years. The experimental results show that our proposed algorithm performs better on the Hong Kong data both quantitatively and qualitatively. Particularly, our algorithm shows better predictive ability, with R2 increased and root mean square error values decreased respectively. PMID:28125034

Measuring the radon concentration in air meting van de radonconcentratie in lucht

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

Aten, J.B.T.; Bierhuizen, H.W.J.; Vanhoek, L.P.

1975-01-01

A simple transportable apparatus for measurement of the radon concentration in the air of a workshop was developed. An air sample is sucked through a filter and the decay curve of the alpha activity is measured. The counting speed 40 min after sampling gives an indication of the radon activity. The apparatus was calibrated by analyzing an analogous decay curve obtained with a big filter and a big air sample, the activity being measured with an anti-coincidence counter. (GRA)

Air ion concentrations in various urban outdoor environments

NASA Astrophysics Data System (ADS)

Ling, Xuan; Jayaratne, Rohan; Morawska, Lidia

2010-06-01

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

Ice-nucleating particle concentrations unaffected by urban air pollution in Beijing, China

NASA Astrophysics Data System (ADS)

Chen, Jie; Wu, Zhijun; Augustin-Bauditz, Stefanie; Grawe, Sarah; Hartmann, Markus; Pei, Xiangyu; Liu, Zirui; Ji, Dongsheng; Wex, Heike

2018-03-01

Exceedingly high levels of PM2.5 with complex chemical composition occur frequently in China. It has been speculated whether anthropogenic PM2.5 may significantly contribute to ice-nucleating particles (INP). However, few studies have focused on the ice-nucleating properties of urban particles. In this work, two ice-nucleating droplet arrays have been used to determine the atmospheric number concentration of INP (NINP) in the range from -6 to -25 °C in Beijing. No correlations between NINP and either PM2.5 or black carbon mass concentrations were found, although both varied by more than a factor of 30 during the sampling period. Similarly, there were no correlations between NINP and either total particle number concentration or number concentrations for particles with diameters > 500 nm. Furthermore, there was no clear difference between day and night samples. All these results indicate that Beijing air pollution did not increase or decrease INP concentrations in the examined temperature range above values observed in nonurban areas; hence, the background INP concentrations might not be anthropogenically influenced as far as urban air pollution is concerned, at least in the examined temperature range.

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).

Methods to reduce the CO(2) concentration of educational buildings utilizing internal ventilation by transferred air.

PubMed

Kalema, T; Viot, M

2014-02-01

The aim of this study is to develop internal ventilation by transferred air to achieve a good indoor climate with low energy consumption in educational buildings with constant air volume (CAV) ventilation. Both measurements of CO2 concentration and a multi-room calculation model are presented. The study analyzes how to use more efficiently the available spaces and the capacity of CAV ventilation systems in existing buildings and the impact this has on the indoor air quality and the energy consumption of the ventilation. The temperature differences can be used to create natural ventilation airflows between neighboring spaces. The behavior of temperature-driven airflows between rooms was studied and included in the calculation model. The effect of openings between neighboring spaces, such as doors or large apertures in the walls, on the CO2 concentration was studied in different classrooms. The air temperatures and CO2 concentrations were measured using a wireless, internet-based measurement system. The multi-room calculation model predicted the CO2 concentration in the rooms, which was then compared with the measured ones. Using transferred air between occupied and unoccupied spaces can noticeably reduce the total mechanical ventilation rates needed to keep a low CO2 concentration. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

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

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

Meklin, Teija; Reponen, Tina; McKinstry, Craig A.

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;more » 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.« less

Impact of ventilation scenario on air exchange rates and on indoor particle number concentrations in an air-conditioned classroom

NASA Astrophysics Data System (ADS)

Guo, H.; Morawska, L.; He, C.; Gilbert, D.

A 2-week intensive measurement campaign of indoor and outdoor air pollution was carried out in September 2006, in a primary school to investigate indoor-outdoor correlations of particle number (PN) concentrations, and the impact of air exchange rate (ACH) on the indoor PN concentration. The ACHs in the classroom for different conditions associated with window opening and the operational status of air conditioners (A/C) and fans were tested. As expected, the lowest ACH (0.12 h -1) was found when the windows were closed and A/C and fans were off. In contrast, the highest ACH (7.92 h -1) was observed when the windows were opened and A/C and fans were all on. The analysis of the PN I/ O ratios at different ACHs in the absence of indoor sources indicates that the mean I/ O ratio was 0.621±0.007 (mean±95% confidence interval) when the windows were closed, and A/C and fans were off; 0.524±0.023 when windows were closed, fans were off and A/C was on; and 0.502±0.029 when windows were closed, A/C was off and fans were on. To further understand the relationship between indoor and outdoor PN concentrations, the impact of outdoor PN concentration on I/ O ratios at different ACHs was investigated. It was found that the relationship between outdoor PN concentration and the I/ O ratio at different ACHs followed a power trendline with an equation of I/ O ratio= A PN out-b ( A and b are coefficients, PN out is outdoor PN concentration), suggesting that the penetration efficiency decreased with increasing outdoor PN concentration. It is the first time we found that when the outdoor PN concentration increased there was an associated increase in the concentration of nano-particles, which have been demonstrated to have higher deposition rates and lower penetration efficiencies. Based on the above equation, the study also showed a significant effect of ACH on indoor PN concentrations under stable outdoor PN concentrations. In general, the higher the ACH was, the lower the indoor PN

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

A METHOD OF ASSESSING AIR TOXICS CONCENTRATIONS IN URBAN AREAS USING MOBILE PLATFORM MEASUREMENTS

EPA Science Inventory

The objective of this paper is to demonstrate an approach to characterize the spatial variability in ambient air concentrations using mobile platform measurements. This approach may be useful for air toxic assessments in Environmental Justice applications, epidemiological studies...

Air concentrations of volatile compounds near oil and gas production: a community-based exploratory study.

PubMed

Macey, Gregg P; Breech, Ruth; Chernaik, Mark; Cox, Caroline; Larson, Denny; Thomas, Deb; Carpenter, David O

2014-10-30

Horizontal drilling, hydraulic fracturing, and other drilling and well stimulation technologies are now used widely in the United States and increasingly in other countries. They enable increases in oil and gas production, but there has been inadequate attention to human health impacts. Air quality near oil and gas operations is an underexplored human health concern for five reasons: (1) prior focus on threats to water quality; (2) an evolving understanding of contributions of certain oil and gas production processes to air quality; (3) limited state air quality monitoring networks; (4) significant variability in air emissions and concentrations; and (5) air quality research that misses impacts important to residents. Preliminary research suggests that volatile compounds, including hazardous air pollutants, are of potential concern. This study differs from prior research in its use of a community-based process to identify sampling locations. Through this approach, we determine concentrations of volatile compounds in air near operations that reflect community concerns and point to the need for more fine-grained and frequent monitoring at points along the production life cycle. Grab and passive air samples were collected by trained volunteers at locations identified through systematic observation of industrial operations and air impacts over the course of resident daily routines. A total of 75 volatile organics were measured using EPA Method TO-15 or TO-3 by gas chromatography/mass spectrometry. Formaldehyde levels were determined using UMEx 100 Passive Samplers. Levels of eight volatile chemicals exceeded federal guidelines under several operational circumstances. Benzene, formaldehyde, and hydrogen sulfide were the most common compounds to exceed acute and other health-based risk levels. Air concentrations of potentially dangerous compounds and chemical mixtures are frequently present near oil and gas production sites. Community-based research can provide an

Evaluating the impact of ambient benzene vapor concentrations on product water from Condensation Water From Air technology.

PubMed

Kinder, Katherine M; Gellasch, Christopher A; Dusenbury, James S; Timmes, Thomas C; Hughes, Thomas M

2017-07-15

Globally, drinking water resources are diminishing in both quantity and quality. This situation has renewed interest in Condensation Water From Air (CWFA) technology, which utilizes water vapor in the air to produce water for both potable and non-potable purposes. However, there are currently insufficient data available to determine the relationship between air contaminants and the rate at which they are transferred from the air into CWFA untreated product water. This study implemented a novel experimental method utilizing an environmental test chamber to evaluate how air quality and temperature affects CWFA untreated product water quality in order to collect data that will inform the type of water treatment required to protect human health. This study found that temperature and benzene air concentration affected the untreated product water from a CWFA system. Benzene vapor concentrations representing a polluted outdoor environment resulted in benzene product water concentrations between 15% and 23% of the USEPA drinking water limit of 5μg/l. In contrast, product water benzene concentrations representing an indoor industrial environment were between 1.4 and 2.4 times higher than the drinking water limit. Lower condenser coil temperatures were correlated with an increased concentration of benzene in the product water. Environmental health professionals and engineers can integrate the results of this assessment to predict benzene concentrations in the product water and take appropriate health protective measures. Published by Elsevier B.V.

Summary and results of the joint WMD-DAC/Alameda County bioterrorism response plan exercise.

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

Manley, Dawn Kataoka; Lipkin, Joel; West, Todd H.

2003-11-01

On June 12,2003, the Alameda County Public Health Department and Sandia National Laboratories/CA jointly conducted an exercise that used a Weapons of Mass Destruction-Decision Analysis Center (WMD-DAC) bioterrorism attack simulation to test the effectiveness of the county's emergency response plan. The exercise was driven by an assumed release (in the vicinity of the Berkeley Marina), and subsequent spread, of a small quantity of aerosolized, weapons-grade anthrax spores. The simulation used several key WMD-DAC capabilities, namely: (1) integration with an atmospheric dispersion model to calculate expected dose levels in the affected areas, (2) a individual-tracking capability for both infected and non-infectedmore » persons as they made decisions, sought treatment, and received prophylaxis drugs, and (3) a user interface that allows exercise participants to affect the scenario evolution and outcome. The analysis of the county's response plan included documenting and reviewing the decisions made by participants during the exercise. Twenty-six local and regional officials representing the health care system, emergency medical services and law enforcement were involved in responding to the simulated attack. The results of this joint effort include lessons learned both by the Alameda County officials regarding implementation of their bioterrorism response plan and by the Sandia representatives about conducting exercises of this type. These observations are reviewed in this report, and they form a basis for providing a better understanding of group/individual decision processes and for identifying effective communication options among decision makers.« less

An enhanced PM 2.5 air quality forecast model based on nonlinear regression and back-trajectory concentrations

NASA Astrophysics Data System (ADS)

Cobourn, W. Geoffrey

2010-08-01

An enhanced PM 2.5 air quality forecast model based on nonlinear regression (NLR) and back-trajectory concentrations has been developed for use in the Louisville, Kentucky metropolitan area. The PM 2.5 air quality forecast model is designed for use in the warm season, from May through September, when PM 2.5 air quality is more likely to be critical for human health. The enhanced PM 2.5 model consists of a basic NLR model, developed for use with an automated air quality forecast system, and an additional parameter based on upwind PM 2.5 concentration, called PM24. The PM24 parameter is designed to be determined manually, by synthesizing backward air trajectory and regional air quality information to compute 24-h back-trajectory concentrations. The PM24 parameter may be used by air quality forecasters to adjust the forecast provided by the automated forecast system. In this study of the 2007 and 2008 forecast seasons, the enhanced model performed well using forecasted meteorological data and PM24 as input. The enhanced PM 2.5 model was compared with three alternative models, including the basic NLR model, the basic NLR model with a persistence parameter added, and the NLR model with persistence and PM24. The two models that included PM24 were of comparable accuracy. The two models incorporating back-trajectory concentrations had lower mean absolute errors and higher rates of detecting unhealthy PM2.5 concentrations compared to the other models.

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. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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

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, SO₄^2-, NO₃, HNO₃, and NH₄⁺ obtained from EPA's CASTNet was examined using an objective, statistically based technique...

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 ...

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...

Correlation between concentrations of n-hexane and toluene in exhaled and environmental air in an occupationally exposed population.

PubMed

Periago, J F; Morente, A; Villanueva, M; Luna, A

1994-01-01

We determined the correlations between the concentrations of n-hexane and toluene in exhaled and environmental air in the shoe manufacturing industry. Data were collected in 1988 and in 1992 from a total of 265 subjects. Environmental air samples were collected with personal diffusive samplers by adsorption on activated charcoal during exposure and from end-expired air (alveolar air) on cartridges of activated charcoal after exposure. Both compounds were desorbed with carbon disulphide and analysed by gas chromatography. Linear regression analyses showed a good correlation between environmental and end-expired air concentrations (r = 0.82 for n-hexane and r = 0.81 for toluene). These correlations allowed us to calculate the concentrations in expired air corresponding to current environmental limit values. The calculated concentrations in end-expired air that correspond to current environmental threshold limit values of 176 mg m-3 for n-hexane and 377 mg m-3 for toluene are 28 mg m-3 (95% confidence limit, 27-29 mg m-3) and 40 mg m-3 (95% confidence limit, 39-41 mg m-3), respectively. Similar correlations were found when the data from the two study periods were analysed separately.

Low-CCN concentration air masses over the eastern North Atlantic: Seasonality, meteorology, and drivers

NASA Astrophysics Data System (ADS)

Wood, Robert; Stemmler, Jayson D.; Rémillard, Jasmine; Jefferson, Anne

2017-01-01

A 20 month cloud condensation nucleus concentration (NCCN) data set from Graciosa Island (39°N, 28°W) in the remote North Atlantic is used to characterize air masses with low cloud condensation nuclei (CCN) concentrations. Low-CCN events are defined as 6 h periods with mean NCCN<20 cm-3 (0.1% supersaturation). A total of 47 low-CCN events are identified. Surface, satellite, and reanalysis data are used to explore the meteorological and cloud context for low-CCN air masses. Low-CCN events occur in all seasons, but their frequency was 3 times higher in December-May than during June-November. Composites show that many of the low-CCN events had a common meteorological basis that involves southerly low-level flow and rather low wind speeds at Graciosa. Anomalously low pressure is situated to the west of Graciosa during these events, but back trajectories and lagged SLP composites indicate that low-CCN air masses often originate as cold air outbreaks to the north and west of Graciosa. Low-CCN events were associated with low cloud droplet concentrations (Nd) at Graciosa, but liquid water path (LWP) during low-CCN events was not systematically different from that at other times. Satellite Nd and LWP estimates from MODIS collocated with Lagrangian back trajectories show systematically lower Nd and higher LWP several days prior to arrival at Graciosa, consistent with the hypothesis that observed low-CCN air masses are often formed by coalescence scavenging in thick warm clouds, often in cold air outbreaks.

Estimated long-term outdoor air pollution concentrations in a cohort study

NASA Astrophysics Data System (ADS)

Beelen, Rob; Hoek, Gerard; Fischer, Paul; Brandt, Piet A. van den; Brunekreef, Bert

Several recent studies associated long-term exposure to air pollution with increased mortality. An ongoing cohort study, the Netherlands Cohort Study on Diet and Cancer (NLCS), was used to study the association between long-term exposure to traffic-related air pollution and mortality. Following on a previous exposure assessment study in the NLCS, we improved the exposure assessment methods. Long-term exposure to nitrogen dioxide (NO 2), nitrogen oxide (NO), black smoke (BS), and sulphur dioxide (SO 2) was estimated. Exposure at each home address ( N=21 868) was considered as a function of a regional, an urban and a local component. The regional component was estimated using inverse distance weighed interpolation of measurement data from regional background sites in a national monitoring network. Regression models with urban concentrations as dependent variables, and number of inhabitants in different buffers and land use variables, derived with a Geographic Information System (GIS), as predictor variables were used to estimate the urban component. The local component was assessed using a GIS and a digital road network with linked traffic intensities. Traffic intensity on the nearest road and on the nearest major road, and the sum of traffic intensity in a buffer of 100 m around each home address were assessed. Further, a quantitative estimate of the local component was estimated. The regression models to estimate the urban component explained 67%, 46%, 49% and 35% of the variances of NO 2, NO, BS, and SO 2 concentrations, respectively. Overall regression models which incorporated the regional, urban and local component explained 84%, 44%, 59% and 56% of the variability in concentrations for NO 2, NO, BS and SO 2, respectively. We were able to develop an exposure assessment model using GIS methods and traffic intensities that explained a large part of the variations in outdoor air pollution concentrations.

Short-term Rn-222 concentration changes in underground spaces with limited air exchange

NASA Astrophysics Data System (ADS)

Fijałkowska-Lichwa, Lidia; Przylibski, Tadeusz A.

2010-05-01

Authors conducted research on radon concentration in two underground structures located in the vicinity of Kletno (Sudety Mts., SW Poland), which are accessible for visitors. One of these structures is Niedźwiedzia (Bear) Cave, and the second one is the part of former uranium mine - Fluorite Adit. Both selected underground structures are characterized by almost constant temperature, changing within the range from +5 to +7° C and also constant relative humidity, close to 100%. Both these parameters testify that air exchange with the atmosphere is very limited. Air exchange is limited particularly in Niedźwiedzia Cave, which microclimate is protected i.e. by applying of locks at the entrance and exit of tourist route. The measurements were conducted between 16.05.2008. and 15.11.2009., by the use of a new Polish equipment - SRDN-3 devices with semiconductor detector. SRDN-3 device records every hour radon concentration as well as atmospheric parameters - relative humidity and temperature. At the same time authors conducted measurements of basic parameters in the open atmosphere close to Niedźwiedzia Cave. Obtained results of atmospheric parameters measurements may be used for both underground structures; because they are located within the distance of about 1 km. Atmospheric parameters were measured by the use of automatic weather station VantagePro2. On the base of conducted research authors corroborate, that the differences of radon concentration in both underground structures reach three orders of magnitude during a year. In Niedźwiedzia Cave these values are in the range from below 88 Bq/m3 (detection limit of the SRDN-3 device) up to 12 kBq/m3. Related values in Fluorite Adit are between < 88 Bq/m3 and 35 kBq/m3. It was observed also the different course of daily radon concentration changes in both structures. Additionally, authors registered that daily course of radon concentration changes differs due to season of the year. Such changes are observed in

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.

Long short-term memory neural network for air pollutant concentration predictions: Method development and evaluation.

PubMed

Li, Xiang; Peng, Ling; Yao, Xiaojing; Cui, Shaolong; Hu, Yuan; You, Chengzeng; Chi, Tianhe

2017-12-01

Air pollutant concentration forecasting is an effective method of protecting public health by providing an early warning against harmful air pollutants. However, existing methods of air pollutant concentration prediction fail to effectively model long-term dependencies, and most neglect spatial correlations. In this paper, a novel long short-term memory neural network extended (LSTME) model that inherently considers spatiotemporal correlations is proposed for air pollutant concentration prediction. Long short-term memory (LSTM) layers were used to automatically extract inherent useful features from historical air pollutant data, and auxiliary data, including meteorological data and time stamp data, were merged into the proposed model to enhance the performance. Hourly PM 2.5 (particulate matter with an aerodynamic diameter less than or equal to 2.5 μm) concentration data collected at 12 air quality monitoring stations in Beijing City from Jan/01/2014 to May/28/2016 were used to validate the effectiveness of the proposed LSTME model. Experiments were performed using the spatiotemporal deep learning (STDL) model, the time delay neural network (TDNN) model, the autoregressive moving average (ARMA) model, the support vector regression (SVR) model, and the traditional LSTM NN model, and a comparison of the results demonstrated that the LSTME model is superior to the other statistics-based models. Additionally, the use of auxiliary data improved model performance. For the one-hour prediction tasks, the proposed model performed well and exhibited a mean absolute percentage error (MAPE) of 11.93%. In addition, we conducted multiscale predictions over different time spans and achieved satisfactory performance, even for 13-24 h prediction tasks (MAPE = 31.47%). Copyright © 2017 Elsevier Ltd. All rights reserved.

Concentrations, sources and human health risk of inhalation exposure to air toxics in Edmonton, Canada.

PubMed

Bari, Md Aynul; Kindzierski, Warren B

2017-04-01

With concern about levels of air pollutants in recent years in the Capital Region of Alberta, an investigation of ambient concentrations, sources and potential human health risk of hazardous air pollutants (HAPs) or air toxics was undertaken in the City of Edmonton over a 5-year period (2009-2013). Mean concentrations of individual HAPs in ambient air including volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs) and trace metals ranged from 0.04 to 1.73 μg/m 3 , 0.01-0.54 ng/m 3 , and 0.05-3.58 ng/m 3 , respectively. Concentrations of benzene, naphthalene, benzo(a)pyrene (BaP), arsenic, manganese and nickel were far below respective annual Alberta Ambient Air Quality Objectives. Carcinogenic and non-carcinogenic risk of air toxics were also compared with risk levels recommended by regulatory agencies. Positive matrix factorization identified six air toxics sources with traffic as the dominant contributor to total HAPs (4.33 μg/m 3 , 42%), followed by background/secondary organic aerosol (SOA) (1.92 μg/m 3 , 25%), fossil fuel combustion (0.92 μg/m 3 , 11%). On high particulate air pollution event days, local traffic was identified as the major contributor to total HAPs compared to background/SOA and fossil fuel combustion. Carcinogenic risk values of traffic, background/SOA and metals industry emissions were above the USEPA acceptable level (1 × 10 -6 ), but below a tolerable risk (1 × 10 -4 ) and Alberta benchmark (1 × 10 -5 ). These findings offer useful preliminary information about current ambient air toxics levels, dominant sources and their potential risk to public health; and this information can support policy makers in the development of appropriate control strategies if required. Copyright © 2017 Elsevier Ltd. All rights reserved.

Concentrations and elemental composition of particulate matter in the Buenos Aires underground system

NASA Astrophysics Data System (ADS)

Murruni, L. G.; Solanes, V.; Debray, M.; Kreiner, A. J.; Davidson, J.; Davidson, M.; Vázquez, M.; Ozafrán, M.

Total suspended particulate (TSP) samples have been collected at six stations in the C and B lines of the Buenos Aires underground system and, almost simultaneously, at six ground level sites outside and nearby the corresponding underground stations, in the Oct 2005/Oct 2006 period. All these samples were analyzed for mass and elemental Fe, Cu, and Zn concentrations by using the Particle Induced X-ray Emission (PIXE) technique. Mostly, TSP concentrations were found to be between 152 μg m -3 (25% percentile) and 270 μg m -3 (75% percentile) in the platform of the stations, while those in outside ambient air oscillated from 55 μg m -3 (25% percentile) to 137 μg m -3 (75% percentile). Moreover, experimental results indicate that TSP levels are comparable to those measured for other underground systems worldwide. Statistical results demonstrate that subway TSP levels are about 3 times larger on average than those for urban ambient air. The TSP levels inside stations and outdoors are poorly correlated, indicating that TSP levels in the metro system are mainly influenced by internal sources. Regarding metal concentrations, the most enriched element in TSP samples was Fe, the levels of which ranged from 36 (25% percentile) to 86 μg m -3 (75% percentile) in Line C stations, while in Line B ones they varied between 8 μg m -3 (25% percentile) and 46 μg m -3 (75% percentile). As a comparison, Fe concentrations in ambient air oscillated between 0.7 μg m -3 (25% percentile) and 1.2 μg m -3 (75% percentile). Other enriched elements include Cu and Zn. With regard to their sources, Fe and Cu have been related to processes taking place inside the subway system, while Zn has been associated with outdoor vehicular traffic. Additionally, concerns about possible health implications based on comparisons to various indoor air quality limits and available toxicological information are discussed.

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.

Effects of ceiling-mounted HEPA-UV air filters on airborne bacteria concentrations in an indoor therapy pool building.

PubMed

Kujundzic, Elmira; Zander, David A; Hernandez, Mark; Angenent, Largus T; Henderson, David E; Miller, Shelly L

2005-02-01

The purpose of this study was to assess the effectiveness of a new generation of high-volume, ceiling-mounted high-efficiency particulate air (HEPA)-ultraviolet (UV) air filters (HUVAFs) for their ability to remove or inactivate bacterial aerosol. In an environmentally controlled full-scale laboratory chamber (87 m3), and an indoor therapy pool building, the mitigation ability of air filters was assessed by comparing concentrations of total bacteria, culturable bacteria, and airborne endotoxin with and without the air filters operating under otherwise similar conditions. Controlled chamber tests with pure cultures of aerosolized Mycobacterium parafortuitum cells showed that the HUVAF unit tested provided an equivalent air-exchange rate of 11 hr(-1). Using this equivalent air-exchange rate as a design basis, three HUVAFs were installed in an indoor therapy pool building for bioaerosol mitigation, and their effectiveness was studied over a 2-year period. The HUVAFs reduced concentrations of culturable bacteria by 69 and 80% during monitoring periods executed in respective years. The HUVAFs reduced concentrations of total bacteria by 12 and 76% during the same monitoring period, respectively. Airborne endotoxin concentrations were not affected by the HUVAF operation.

Indoor air-assessment: Indoor concentrations of environmental carcinogens

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

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,more » 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.« less

Atmospheric concentrations and air-sea exchanges of nonylphenol, tertiary octylphenol and nonylphenol monoethoxylate in the North Sea.

PubMed

Xie, Zhiyong; Lakaschus, Soenke; Ebinghaus, Ralf; Caba, Armando; Ruck, Wolfgang

2006-07-01

Concentrations of nonylphenol isomers (NP), tertiary octylphenol (t-OP) and nonylphenol monoethoxylate isomers (NP1EO) have been simultaneously determined in the sea water and atmosphere of the North Sea. A decreasing concentration profile appeared following the distance increasing from the coast to the central part of the North Sea. Air-sea exchanges of t-OP and NP were estimated using the two-film resistance model based upon relative air-water concentrations and experimentally derived Henry's law constant. The average of air-sea exchange fluxes was -12+/-6 ng m(-2)day(-1) for t-OP and -39+/-19 ng m(-2)day(-1) for NP, which indicates a net deposition is occurring. These results suggest that the air-sea vapour exchange is an important process that intervenes in the mass balance of alkylphenols in the North Sea.

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.

Local emission of primary air pollutants and its contribution to wet deposition and concentrations of aerosols and gases in ambient air in Japan

NASA Astrophysics Data System (ADS)

Aikawa, Masahide; Hiraki, Takatoshi; Tomoyose, Nobutaka; Ohizumi, Tsuyoshi; Noguchi, Izumi; Murano, Kentaro; Mukai, Hitoshi

2013-11-01

We studied wet deposition by precipitation and the concentrations of aerosols and gases in ambient air in relation to the primary air pollutants discharged from domestic areas. The concentrations of aerosols and gases were influenced by nearby emissions except for non-sea-salt SO, which is transported long distances. The area facing the Sea of Japan showed much larger wet deposition than other areas, although the domestic emissions of the primary air pollutants there were small and showed a peak in wet deposition from October to March, as distinct from April to September in other areas. We performed the correlation analyses between wet deposition of each component and the product of the concentrations of corresponding aerosols and gases in ambient air and the two-thirds power of the precipitation. From the results, following scavenging processes were suggested. • Sulfate and ammonium were scavenged in precipitation as particulate matter such as (NH4)2SO4 and NH4HSO4. • Nitrate was scavenged mainly in precipitation through gaseous HNO3. • Ammonium was complementarily scavenged in precipitation through aerosols such as (NH4)2SO4 and NH4HSO4 and through gaseous NH3.

Human-machine interface (HMI) report for 241-SY-101 data acquisition [and control] system (DACS) upgrade study

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

Truitt, R.W.

1997-10-22

This report provides an independent evaluation of information for a Windows based Human Machine Interface (HMI) to replace the existing DOS based Iconics HMI currently used in the Data Acquisition and Control System (DACS) used at Tank 241-SY-101. A fundamental reason for this evaluation is because of the difficulty of maintaining the system with obsolete, unsupported software. The DACS uses a software operator interface (Genesis for DOS HMI) that is no longer supported by its manufacturer, Iconics. In addition to its obsolescence, it is complex and difficult to train additional personnel on. The FY 1997 budget allocated $40K for phasemore » 1 of a software/hardware upgrade that would have allowed the old DOS based system to be replaced by a current Windows based system. Unfortunately, budget constraints during FY 1997 has prompted deferral of the upgrade. The upgrade needs to be performed at the earliest possible time, before other failures render the system useless. Once completed, the upgrade could alleviate other concerns: spare pump software may be able to be incorporated into the same software as the existing pump, thereby eliminating the parallel path dilemma; and the newer, less complex software should expedite training of future personnel, and in the process, require that less technical time be required to maintain the system.« less

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.

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

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

Hodgson, A.T.; Faulkner, D.; Sullivan, D.P.

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 concentrationsmore » were not observed for most of the abundant VOCs. This result emphasizes the importance of source control measures for limiting VOC concentrations in buildings.« less

[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.

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.

Air change rates of motor vehicles and in-vehicle pollutant concentrations from secondhand smoke.

PubMed

Ott, Wayne; Klepeis, Neil; Switzer, Paul

2008-05-01

The air change rates of motor vehicles are relevant to the sheltering effect from air pollutants entering from outside a vehicle and also to the interior concentrations from any sources inside its passenger compartment. We made more than 100 air change rate measurements on four motor vehicles under moving and stationary conditions; we also measured the carbon monoxide (CO) and fine particle (PM(2.5)) decay rates from 14 cigarettes smoked inside the vehicle. With the vehicle stationary and the fan off, the ventilation rate in air changes per hour (ACH) was less than 1 h(-1) with the windows closed and increased to 6.5 h(-1) with one window fully opened. The vehicle speed, window position, ventilation system, and air conditioner setting was found to affect the ACH. For closed windows and passive ventilation (fan off and no recirculation), the ACH was linearly related to the vehicle speed over the range from 15 to 72 mph (25 to 116 km h(-1)). With a vehicle moving, windows closed, and the ventilation system off (or the air conditioner set to AC Max), the ACH was less than 6.6 h(-1) for speeds ranging from 20 to 72 mph (32 to 116 km h(-1)). Opening a single window by 3'' (7.6 cm) increased the ACH by 8-16 times. For the 14 cigarettes smoked in vehicles, the deposition rate k and the air change rate a were correlated, following the equation k=1.3a (R(2)=82%; n=14). With recirculation on (or AC Max) and closed windows, the interior PM(2.5) concentration exceeded 2000 microg m(-3) momentarily for all cigarettes tested, regardless of speed. The concentration time series measured inside the vehicle followed the mathematical solutions of the indoor mass balance model, and the 24-h average personal exposure to PM(2.5) could exceed 35 microg m(-3) for just two cigarettes smoked inside the vehicle.

Extraordinary Tools for Extraordinary Science: The Impact ofSciDAC on Accelerator Science&Technology

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

Ryne, Robert D.

2006-08-10

Particle accelerators are among the most complex and versatile instruments of scientific exploration. They have enabled remarkable scientific discoveries and important technological advances that span all programs within the DOE Office of Science (DOE/SC). The importance of accelerators to the DOE/SC mission is evident from an examination of the DOE document, ''Facilities for the Future of Science: A Twenty-Year Outlook''. Of the 28 facilities listed, 13 involve accelerators. Thanks to SciDAC, a powerful suite of parallel simulation tools has been developed that represent a paradigm shift in computational accelerator science. Simulations that used to take weeks or more now takemore » hours, and simulations that were once thought impossible are now performed routinely. These codes have been applied to many important projects of DOE/SC including existing facilities (the Tevatron complex, the Relativistic Heavy Ion Collider), facilities under construction (the Large Hadron Collider, the Spallation Neutron Source, the Linac Coherent Light Source), and to future facilities (the International Linear Collider, the Rare Isotope Accelerator). The new codes have also been used to explore innovative approaches to charged particle acceleration. These approaches, based on the extremely intense fields that can be present in lasers and plasmas, may one day provide a path to the outermost reaches of the energy frontier. Furthermore, they could lead to compact, high-gradient accelerators that would have huge consequences for US science and technology, industry, and medicine. In this talk I will describe the new accelerator modeling capabilities developed under SciDAC, the essential role of multi-disciplinary collaboration with applied mathematicians, computer scientists, and other IT experts in developing these capabilities, and provide examples of how the codes have been used to support DOE/SC accelerator projects.« less

Three-dimensional anisotropy contrast periodically rotated overlapping parallel lines with enhanced reconstruction (3DAC PROPELLER) on a 3.0T system: a new modality for routine clinical neuroimaging.

PubMed

Nakada, Tsutomu; Matsuzawa, Hitoshi; Fujii, Yukihiko; Takahashi, Hitoshi; Nishizawa, Masatoyo; Kwee, Ingrid L

2006-07-01

Clinical magnetic resonance imaging (MRI) has recently entered the "high-field" era, and systems equipped with 3.0-4.0T superconductive magnets are becoming the gold standard for diagnostic imaging. While higher signal-to-noise ratio (S/N) is a definite advantage of higher field systems, higher susceptibility effect remains to be a significant trade-off. To take advantage of a higher field system in performing routine clinical images of higher anatomical resolution, we implemented a vector contrast image technique to 3.0T imaging, three-dimensional anisotropy contrast (3DAC), with a PROPELLER (Periodically Rotated Overlapping Parallel Lines with Enhanced Reconstruction) sequence, a method capable of effectively eliminating undesired artifacts on rapid diffusion imaging sequences. One hundred subjects (20 normal volunteers and 80 volunteers with various central nervous system diseases) participated in the study. Anisotropic diffusion-weighted PROPELLER images were obtained on a General Electric (Waukesha, WI, USA) Signa 3.0T for each axis, with b-value of 1100 sec/mm(2). Subsequently, 3DAC images were constructed using in-house software written on MATLAB (MathWorks, Natick, MA, USA). The vector contrast allows for providing exquisite anatomical detail illustrated by clear identification of all major tracts through the entire brain. 3DAC images provide better anatomical resolution for brainstem glioma than higher-resolution T2 reversed images. Degenerative processes of disease-specific tracts were clearly identified as illustrated in cases of multiple system atrophy and Joseph-Machado disease. Anatomical images of significantly higher resolution than the best current standard, T2 reversed images, were successfully obtained. As a technique readily applicable under routine clinical setting, 3DAC PROPELLER on a 3.0T system will be a powerful addition to diagnostic imaging.

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

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

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...

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...

Atmospheric CO2 Concentrations--The Canadian Background Air Pollution Monitoring Network (1993) (NDP-034)

DOE Data Explorer

Trivett, N. B. A. [Environment Canada, Atmospheric Environment Service, Downsview, Ontario, Canada; Hudec, V. C. [Environment Canada, Atmospheric Environment Service, Downsview, Ontario, Canada; Wong, C. S. [Marine Carbon Research Centre, Institute of Ocean Sciences, Sidney, British Columbia, Canada

1993-01-01

Flask air samples collected at roughly weekly intervals at three Canadian sites [Alert, Northwest Territories (July 1975 through July 1992); Sable Island, Nova Scotia (March 1975 through July 1992); and Cape St. James, British Columbia (May 1979 through July 1992)] were analyzed for CO2 concentration with the measurements directly traceable to the WMO primary CO2 standards. Each record includes the date, atmospheric CO2 concentration, and flask classification code. They provide an accurate record of CO2 concentration levels in Canada during the past two decades. Because these data are directly traceable to WMO standards, this record may be compared with records from other Background Air Pollution Monitoring Network (BAPMoN) stations. The data are in three files (one for each of the monitoring stations) ranging in size from 9.4 to 20.1 kB.

Binding mode and thermodynamic studies on the interaction of the anticancer drug dacarbazine and dacarbazine-Cu(II) complex with single and double stranded DNA.

PubMed

Temerk, Yassien; Ibrahim, Hossieny

2014-07-01

The binding mode and thermodynamic characteristics of the anticancer drug dacarbazine (Dac) with double and single stranded DNA were investigated in the absence and presence of Cu(II) using cyclic voltammetry, square wave voltammetry and fluorescence spectroscopy. The interaction of Dac and Dac-Cu(II) complex with dsDNA indicated their intercalation into the base stacking domain of dsDNA double helix and the strength of interaction is independent on the ionic strength. The interaction of Dac with dsDNA in the presence of Cu(II) leads to a much stronger intercalation. The interaction mode of Dac molecules with ssDNA is electrostatic attraction via negative phosphate on the exterior of the ssDNA with Dac. The binding constants, stoichiometric coefficients and thermodynamic parameters of Dac and Dac-Cu(II) complex with dsDNA and ssDNA were evaluated. Comparison of the mode interaction of Dac with dsDNA and ssDNA was discussed. The decrease of peak current of Dac was proportional to DNA concentration, which was applied for determination of dsDNA and ssDNA concentration. Copyright © 2014 Elsevier B.V. All rights reserved.

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.

[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.

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.

Implications of alternative assumptions regarding future air pollution control in scenarios similar to the Representative Concentration Pathways

NASA Astrophysics Data System (ADS)

Chuwah, Clifford; van Noije, Twan; van Vuuren, Detlef P.; Hazeleger, Wilco; Strunk, Achim; Deetman, Sebastiaan; Beltran, Angelica Mendoza; van Vliet, Jasper

2013-11-01

The uncertain, future development of emissions of short-lived trace gases and aerosols forms a key factor for future air quality and climate forcing. The Representative Concentration Pathways (RCPs) only explore part of this range as they all assume that worldwide ambitious air pollution control policies will be implemented. In this study, we explore how different assumptions on future air pollution policy and climate policy lead to different concentrations of air pollutants for a set of RCP-like scenarios developed using the IMAGE model. These scenarios combine low and high air pollution variants of the scenarios with radiative forcing targets in 2100 of 2.6 W m-2 and 6.0 W m-2. Simulations using the global atmospheric chemistry and transport model TM5 for the present-day climate show that both climate mitigation and air pollution control policies have large-scale effects on pollutant concentrations, often of similar magnitude. If no further air pollution policies would be implemented, pollution levels could be considerably higher than in the RCPs, especially in Asia. Air pollution control measures could significantly reduce the warming by tropospheric ozone and black carbon and the cooling by sulphate by 2020, and in the longer term contribute to enhanced warming by methane. These effects tend to cancel each other on a global scale. According to our estimates the effect of the worldwide implementation of air pollution control measures on the total global mean direct radiative forcing in 2050 is +0.09 W m-2 in the 6.0 W m-2 scenario and -0.16 W m-2 in the 2.6 W m-2 scenario.

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). © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Laboratory and on-road evaluations of cabin air filters using number and surface area concentration monitors.

PubMed

Qi, Chaolong; Stanley, Nick; Pui, David Y H; Kuehn, Thomas H

2008-06-01

An automotive cabin air filter's effectiveness for removing airborne particles was determined both in a laboratory wind tunnel and in vehicle on-road tests. The most penetrating particle size for the test filter was approximately 350 nm, where the filtration efficiency was 22.9 and 17.4% at medium and high fan speeds, respectively. The filtration efficiency increased for smaller particles and was 43.9% for 100 nm and 72.0% for 20 nm particles at a medium fan speed. We determined the reduction in passenger exposure to particles while driving in freeway traffic caused by a vehicle ventilation system with a cabin air filter installed. Both particle number and surface area concentration measurements were made inside the cabin and in the surrounding air. At medium fan speed, the number and surface area concentration-based exposure reductions were 65.6 +/- 6.0% and 60.6 +/- 9.4%, respectively. To distinguish the exposure reduction contribution from the filter alone and the remainder of the ventilation system, we also performed tests with and without the filter in place using the surface area monitors. The ventilation system operating in the recirculation mode with the cabin air filter installed provided the maximum protection, reducing the cabin particle concentration exponentially over time and usually taking only 3 min to reach 10 microm2/cm3 (a typical office air condition) under medium fan speed.

[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.

Radon daughters' concentration in air and exposure of joggers at the university campus of Bangalore, India.

PubMed

Ashok, G V; Nagaiah, N; Shiva Prasad, N G

2008-09-01

The concentration of radon daughters in outdoor air was measured continuously from January 2006 to December 2006 near the Department of Physics, Bangalore University campus, Bangalore. The concentration was measured by collecting air samples at a height of 1 m above the ground level on a glass micro fibre filter paper with a known air flow rate. The results show that the radon progeny concentration exhibits distinct seasonal and diurnal variations that are predominantly caused by changes in the temperature gradient at the soil-atmosphere interface. The concentration was found to be high from 20.00 to 8.00 hrs, when the turbulence mixing was minimum and low during the rest of the time. In terms of the monthly concentration, January was found to be the highest with September/August being the lowest. The diurnal variations in the concentrations of radon progeny were found to exhibit positive correlation with the relative humidity and anti-correlation with the atmospheric temperature. From the measured concentration, an attempt was made to establish the annual effective dose to the general public of the region and was found to be 0.085 mSv/a. In addition, an attempt was also made for the first time to study the variation of inhalation dose with respect to the physical activity levels. Results show that in the light of both the effect of chemical pollutants and radiation dose due to inhalation of radon daughters, evening jogging is advisable.

Rapid Healing of Cutaneous Leishmaniasis by High-Frequency Electrocauterization and Hydrogel Wound Care with or without DAC N-055: A Randomized Controlled Phase IIa Trial in Kabul

PubMed Central

Steiner, Reto; Wentker, Pia; Mahfuz, Farouq; Stahl, Hans-Christian; Amin, Faquir Mohammad; Bogdan, Christian; Stahl, Kurt-Wilhelm

2014-01-01

Background Anthroponotic cutaneous leishmaniasis (CL) due to Leishmania (L.) tropica infection is a chronic, frequently disfiguring skin disease with limited therapeutic options. In endemic countries healing of ulcerative lesions is often delayed by bacterial and/or fungal infections. Here, we studied a novel therapeutic concept to prevent superinfections, accelerate wound closure, and improve the cosmetic outcome of ACL. Methodology/Principal Findings From 2004 to 2008 we performed a two-armed, randomized, double-blinded, phase IIa trial in Kabul, Afghanistan, with patients suffering from L. tropica CL. The skin lesions were treated with bipolar high-frequency electrocauterization (EC) followed by daily moist-wound-treatment (MWT) with polyacrylate hydrogel with (group I) or without (group II) pharmaceutical sodium chlorite (DAC N-055). Patients below age 5, with facial lesions, pregnancy, or serious comorbidities were excluded. The primary, photodocumented outcome was the time needed for complete lesion epithelialization. Biopsies for parasitological and (immuno)histopathological analyses were taken prior to EC (1st), after wound closure (2nd) and after 6 months (3rd). The mean duration for complete wound closure was short and indifferent in group I (59 patients, 43.1 d) and II (54 patients, 42 d; p = 0.83). In patients with Leishmania-positive 2nd biopsies DAC N-055 caused a more rapid wound epithelialization (37.2 d vs. 58.3 d; p = 0.08). Superinfections occurred in both groups at the same rate (8.8%). Except for one patient, reulcerations (10.2% in group I, 18.5% in group II; p = 0.158) were confined to cases with persistent high parasite loads after healing. In vitro, DAC N-055 showed a leishmanicidal effect on pro- and amastigotes. Conclusions/Significance Compared to previous results with intralesional antimony injections, the EC plus MWT protocol led to more rapid wound closure. The tentatively lower rate of relapses and the acceleration of

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.

Reference natural radionuclide concentrations in Australian soils and derived terrestrial air kerma rate.

PubMed

Kleinschmidt, R

2017-06-01

Sediment from drainage catchment outlets has been shown to be a useful means of sampling large land masses for soil composition. Naturally occurring radioactive material concentrations (uranium, thorium and potassium-40) in soil have been collated and converted to activity concentrations using data collected from the National Geochemistry Survey of Australia. Average terrestrial air kerma rate data are derived using the elemental concentration data, and is tabulated for Australia and states for use as baseline reference information. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

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. © 2015 Blackwell Verlag GmbH.

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

PubMed

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

2012-06-01

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. Environmental tobacco smoke (ETS) increased particulate matter (PM) levels by about 14 μg/m3 and was often detected using ETS-specific tracers despite restrictions on smoking in the house as reported on questionnaires administered to caregivers. PM concentrations depended on season, filter usage, relative humidity, air exchange ratios, number of children, outdoor PM levels, sweeping/dusting, and presence of a central air conditioner (AC). Free-standing air filters can be an effective intervention that provides substantial reductions in PM concentrations if the filters are used. However, filter use was variable across the study population and declined over the study duration, and

Concentrations and deposition of nitrogenous air pollutants in a ponderosa/Jeffrey pine canopy

Treesearch

Andrzej Bytnerowicz; Mark E. Fenn; Michael J. Arbaugh

1998-01-01

Nitrogenous (N) air pollutant concentrations and surface deposition of nitrate (NO3-) and ammonium (NH4+) to branches of ponderosa pine (Pinus ponderosa Dougl. ex. Laws.) seedlings were measured on a vertical transect in a mature ponderosa/Jeffrey (...

Factors determining the concentration and chemical composition of particulate matter in the air of selected service facilities

NASA Astrophysics Data System (ADS)

Rogula-Kopiec, Patrycja; Pastuszka, Józef; Mathews, Barbara; Widziewicz, Kamila

2018-01-01

The link between increased morbidity and mortality and increasing concentrations of particulate matter (PM) resulted in great attention being paid to the presence and physicochemical properties of PM in closed rooms, where people spends most of their time. The least recognized group of such indoor environments are small service facilities. The aim of this study was to identify factors which determine the concentration, chemical composition and sources of PM in the air of different service facilities: restaurant kitchen, printing office and beauty salon. The average PM concentration measured in the kitchen was 5-fold (PM4, particle fraction ≥ 4 μm) and 5.3-fold (TSP, total PM) greater than the average concentration of these PM fractions over the same period. During the same measurement period in the printing office and in the beauty salon, the mean PM concentration was 10- and 4-fold (PM4) and 8- and 3-fold (TSP) respectively greater than the mean concentration of these PM fractions in outdoor air. In both facilities the main source of PM macro-components, especially organic carbon, were chemicals, which are normally used in such places - solvents, varnishes, paints, etc. The influence of some metals inflow from the outdoor air into indoor environment of those facilities was also recognized.

Irreversible sorption of trace concentrations of perfluorocarboxylic acids to fiber filters used for air sampling

NASA Astrophysics Data System (ADS)

Arp, Hans Peter H.; Goss, Kai-Uwe

Due to the apparent environmental omnipresence of perfluorocarboxylic acids (PFAs), an increasing number of researchers are investigating their ambient particle- and gas-phase concentrations. Typically this is done using a high-volume air sampler equipped with Quartz Fiber Filters (QFFs) or Glass Fiber Filters (GFFs) to sample the particle-bound PFAs and downstream sorbents to sample the gas-phase PFAs. This study reports that at trace, ambient concentrations gas-phase PFAs sorb to QFFs and GFFs irreversibly and hardly pass through these filters to the downstream sorbents. As a consequence, it is not possible to distinguish between particle- and gas-phase concentrations, or to distinguish concentrations on different particle size fractions, unless precautions are taken. Failure to take such precautions could have already caused reported data to be misinterpreted. Here it is also reported that deactivating QFFs and GFFs with a silylating agent renders them suitable for sampling PFAs. Based on the presented study, a series of recommendations for air-sampling PFAs are provided.

Extraordinary tools for extraordinary science: the impact of SciDAC on accelerator science and technology

NASA Astrophysics Data System (ADS)

Ryne, Robert D.

2006-09-01

Particle accelerators are among the most complex and versatile instruments of scientific exploration. They have enabled remarkable scientific discoveries and important technological advances that span all programs within the DOE Office of Science (DOE/SC). The importance of accelerators to the DOE/SC mission is evident from an examination of the DOE document, ''Facilities for the Future of Science: A Twenty-Year Outlook.'' Of the 28 facilities listed, 13 involve accelerators. Thanks to SciDAC, a powerful suite of parallel simulation tools has been developed that represent a paradigm shift in computational accelerator science. Simulations that used to take weeks or more now take hours, and simulations that were once thought impossible are now performed routinely. These codes have been applied to many important projects of DOE/SC including existing facilities (the Tevatron complex, the Relativistic Heavy Ion Collider), facilities under construction (the Large Hadron Collider, the Spallation Neutron Source, the Linac Coherent Light Source), and to future facilities (the International Linear Collider, the Rare Isotope Accelerator). The new codes have also been used to explore innovative approaches to charged particle acceleration. These approaches, based on the extremely intense fields that can be present in lasers and plasmas, may one day provide a path to the outermost reaches of the energy frontier. Furthermore, they could lead to compact, high-gradient accelerators that would have huge consequences for US science and technology, industry, and medicine. In this talk I will describe the new accelerator modeling capabilities developed under SciDAC, the essential role of multi-disciplinary collaboration with applied mathematicians, computer scientists, and other IT experts in developing these capabilities, and provide examples of how the codes have been used to support DOE/SC accelerator projects.

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

Effects of tetrahydrouridine on pharmacokinetics and pharmacodynamics of oral decitabine

PubMed Central

Lavelle, Donald; Vaitkus, Kestis; Ling, Yonghua; Ruiz, Maria A.; Mahfouz, Reda; Ng, Kwok Peng; Negrotto, Soledad; Smith, Nicola; Terse, Pramod; Engelke, Kory J.; Covey, Joseph; Chan, Kenneth K.; DeSimone, Joseph

2012-01-01

The deoxycytidine analog decitabine (DAC) can deplete DNA methyl-transferase 1 (DNMT1) and thereby modify cellular epigenetics, gene expression, and differentiation. However, a barrier to efficacious and accessible DNMT1-targeted therapy is cytidine deaminase, an enzyme highly expressed in the intestine and liver that rapidly metabolizes DAC into inactive uridine counterparts, severely limiting exposure time and oral bioavailability. In the present study, the effects of tetrahydrouridine (THU), a competitive inhibitor of cytidine deaminase, on the pharmacokinetics and pharmacodynamics of oral DAC were evaluated in mice and nonhuman primates. Oral administration of THU before oral DAC extended DAC absorption time and widened the concentration-time profile, increasing the exposure time for S-phase–specific depletion of DNMT1 without the high peak DAC levels that can cause DNA damage and cytotoxicity. THU also decreased interindividual variability in pharmacokinetics seen with DAC alone. One potential clinical application of DNMT1-targeted therapy is to increase fetal hemoglobin and treat hemoglobinopathy. Oral THU-DAC at a dose that would produce peak DAC concentrations of less than 0.2μM administered 2×/wk for 8 weeks to nonhuman primates was not myelotoxic, hypomethylated DNA in the γ-globin gene promoter, and produced large cumulative increases in fetal hemoglobin. Combining oral THU with oral DAC changes DAC pharmacology in a manner that may facilitate accessible noncytotoxic DNMT1-targeted therapy. PMID:22160381

Methanethiol Concentrations and Sea-Air Fluxes in the Subarctic NE Pacific Ocean

NASA Astrophysics Data System (ADS)

Kiene, R. P.; Williams, T. E.; Esson, K.; Tortell, P. D.; Dacey, J. W. H.

2017-12-01

Exchange of volatile organic sulfur from the ocean to the atmosphere impacts the global sulfur cycle and the climate system and is thought to occur mainly via the gas dimethylsulfide (DMS). DMS is produced during degradation of the abundant phytoplankton osmolyte dimethylsulfoniopropionate (DMSP) but bacteria can also convert dissolved DMSP into the sulfur gas methanethiol (MeSH). MeSH has been difficult to measure in seawater because of its high chemical and biological reactivity and, thus, information on MeSH concentrations, distribution and sea-air fluxes is limited. We measured MeSH in the northeast subarctic Pacific Ocean in July 2016, along transects with strong phytoplankton abundance gradients. Water samples obtained with Niskin bottles were analyzed for MeSH by purge-and-trap gas chromatography. Depth profiles showed that MeSH concentrations were high near the surface and declined with depth. Surface waters (5 m depth) had an average MeSH concentration of 0.75 nM with concentrations reaching up to 3nM. MeSH concentrations were correlated (r = 0.47) with microbial turnover of dissolved DMSP which ranged up to 236 nM per day. MeSH was also correlated with total DMSP (r = 0.93) and dissolved DMS (r = 0.63), supporting the conclusion that DMSP was a major precursor of MeSH. Surface water MeSH:DMS concentration ratios averaged 0.19 and ranged up to 0.50 indicating that MeSH was a significant fraction of the volatile sulfur pool in surface waters. Sea-air fluxes of MeSH averaged 15% of the combined DMS+MeSH flux, therefore MeSH contributed an important fraction of the sulfur emitted to the atmosphere from the subarctic NE Pacific Ocean.

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

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

Singer, Brett C.; Destaillat, Hugo; Hodgson, Alfred T.

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, fractionalmore » 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}.« less

Concentrations in ambient air and emissions of cyclic volatile methylsiloxanes in Zurich, Switzerland.

PubMed

Buser, Andreas M; Kierkegaard, Amelie; Bogdal, Christian; MacLeod, Matthew; Scheringer, Martin; Hungerbühler, Konrad

2013-07-02

Tens of thousands of tonnes of cyclic volatile methylsiloxanes (cVMS) are used each year globally, which leads to high and continuous cVMS emissions to air. However, field measurements of cVMS in air and empirical information about emission rates to air are still limited. Here we present measurements of decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6) in air for Zurich, Switzerland. The measurements were performed in January and February 2011 over a period of eight days and at two sites (city center and background) with a temporal resolution of 6-12 h. Concentrations of D5 and D6 are higher in the center of Zurich and range from 100 to 650 ng m(-3) and from 10 to 79 ng m(-3), respectively. These values are among the highest levels of D5 and D6 reported in the literature. In a second step, we used a multimedia environmental fate model parametrized for the region of Zurich to interpret the levels and time trends in the cVMS concentrations and to back-calculate the emission rates of D5 and D6 from the city of Zurich. The average emission rates obtained for D5 and D6 are 120 kg d(-1) and 14 kg d(-1), respectively, which corresponds to per-capita emissions of 310 mg capita(-1) d(-1) for D5 and 36 mg capita(-1) d(-1) for D6.

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...

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.

Multisite study of particle number concentrations in urban air.

PubMed

Harrison, Roy M; Jones, Alan M

2005-08-15

Particle number concentration data are reported from a total of eight urban site locations in the United Kingdom. Of these, six are central urban background sites, while one is an urban street canyon (Marylebone Road) and another is influenced by both a motorway and a steelworks (Port Talbot). The concentrations are generally of a similar order to those reported in the literature, although higher than those in some of the other studies. Highest concentrations are at the Marylebone Road site and lowest are at the Port Talbot site. The central urban background locations lie somewhere between with concentrations typically around 20 000 cm(-3). A seasonal pattern affects all sites, with highest concentrations in the winter months and lowest concentrations in the summer. Data from all sites show a diurnal variation with a morning rush hour peak typical of an anthropogenic pollutant. When the dilution effects of windspeed are accounted for, the data show little directionality at the central urban background sites indicating the influence of sources from all directions as might be expected if the major source were road traffic. At the London Marylebone Road site there is high directionality driven by the air circulation in the street canyon, and at the Port Talbot site different diurnal patterns are seen for particle number count and PM10 influenced by emissions from road traffic (particle number count) and the steelworks (PM10) and local meteorological factors. Hourly particle number concentrations are generally only weakly correlated to NO(x) and PM10, with the former showing a slightly closer relationship. Correlations between daily average particle number count and PM10 were also weak. Episodes of high PM10 concentration in summer typically show low particle number concentrations consistent with transport of accumulation mode secondary aerosol, while winter episodes are frequently associated with high PM10 and particle number count arising from poor dispersion of

Indoor dust and air concentrations of endotoxin in urban and rural environments.

PubMed

Barnig, C; Reboux, G; Roussel, S; Casset, A; Sohy, C; Dalphin, J-C; de Blay, F

2013-03-01

Rural dairy farming is associated with high exposure to indoor endotoxins as compared to rural nonfarming houses and urban houses. The time spent on the mattress (7 h for an adult) and of the proximity of the contaminated source should be taken into account with the other causes of exposure. Studies in European children from a farming background have shown that these children have a reduced risk of asthma and atopic sensitization compared to their urban counterparts. It has been suggested that this might be due to exposure to high levels of endotoxin in the farming environment. The aim of this study was to compare indoor endotoxin concentrations in air and dust samples from randomly selected urban and rural dwellings. In the rural area, endotoxins were analysed in farmhouses and nonfarmhouses as well as housing characteristics, lifestyle factors and agricultural practices likely to influence air and dust endotoxin levels. Endotoxin levels were significantly higher in floor (6600 ± 6100 vs 3600 ± 5600 and 3800 ± 17,000 ng g⁻¹; P < 0·001) and mattress dust (2900 ± 4100 vs 1100 ± 2400 and 800 ± 2600 ng g⁻¹; P < 0·001) from farmhouses compared to other rural and urban homes. However, no difference was observed between endotoxin concentrations in the air of urban and rural houses, and airborne endotoxin levels did not correlate to dust levels. Lack of ventilation and direct entry into the house were correlated with an increase in dust endotoxin levels. These results confirm that dairy farming is associated with high exposure to endotoxins in indoor dust samples. No difference was observed between indoor airborne concentrations between urban and rural houses. These results suggest that measuring endotoxin in dust is the most relevant method to assess endotoxin exposure. © 2012 The Society for Applied Microbiology.

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

Concentrations and variability of organophosphate esters, halogenated flame retardants, and polybrominated diphenyl ethers in indoor and outdoor air in Stockholm, Sweden.

PubMed

Wong, Fiona; de Wit, Cynthia A; Newton, Seth R

2018-05-10

We investigated the concentrations and temporal variability of organophospate esters (OPEs), halogenated flame retardants (HFRs) and polybrominated diphenyl ethers (PBDEs) in indoor and outdoor urban air in Stockholm, Sweden over one year (2014-2015) period. The median concentrations of the three target chemical groups (OPEs, HFRs, PBDEs) were 1-2 orders of magnitude higher in indoor air than outdoor urban air. OPEs were the most abundant target FRs with median concentrations in indoor (Σ 10 OPE = 340 000 pg/m 3 ) and outdoor urban (Σ 10 OPEs = 3100 pg/m 3 ) air, being 3 orders of magnitude greater than for HFRs in indoor (Σ 15 HFRs = 120 pg/m 3 ) and outdoor urban (Σ 15 HFRs = 1.6 pg/m 3 ) air. In indoor air, PBDE concentrations (Σ 17 PBDEs = 33 pg/m 3 ) were lower than for the HFRs, but in outdoor urban air, concentrations (Σ 17 PBDEs = 1.1 pg/m 3 ) were similar to HFRs. The most abundant OPEs in both the indoor and outdoor urban air were tris(2-butoxyethyl)phosphate (TBOEP), tris(chloroisopropyl)phosphate (TCIPP), tris(2-chloroethyl)phosphate (TCEP), tri-n-butyl-phosphate (TnBP), triphenyl phosphate (TPhP) and tris(1,3-dichloroisopropyl)phosphate (TDCIPP). TCIPP in indoor air was found in the highest concentrations and showed the greatest temporal variability, which ranged from 85 000 to 1 900 000 pg/m 3 during the one-year sampling period. We speculate that activities in the building, e.g. floor cleaning, polishing, construction, introduction of new electronics and changes in ventilation rate could explain its variation. Some OPEs (TnBP, TCEP, TCIPP, TDCIPP and TPhP), HFRs/PBDEs (pentabromotoluene, 2, 3-dibromopropyl 2, 4, 6-tribromophenyl ether, hexabromobenzene, BDE-28, -47, and -99) in outdoor urban air showed seasonality, with increased concentrations during the warm period (p < 0.05, Pearson's r ranged from -0.45 to -0.91). The observed seasonality for OPEs was probably due to changes in primary

Aerosol concentration measurements and correlations with air mass trajectories at the Pierre Auger Observatory

NASA Astrophysics Data System (ADS)

Micheletti, M. I.; Louedec, K.; Freire, M.; Vitale, P.; Piacentini, R. D.

2017-06-01

Aerosols play an important role in radiative transfer processes involved in different fields of study. In particular, their influence is crucial in the attenuation of light at astronomical and astrophysical observatories, and has to be taken into account in light transfer models employed to reconstruct the signals. The Andean Argentinean region is increasingly being considered as a good candidate to host such facilities, as well as the ones for solar-energy resources, and an adequate knowledge of aerosols characteristics there is needed, but it is not always possible due to the vast area involved and the scarce atmospheric data at ground. The aim of this work is to find correlations between aerosol data and particle trajectories that can give an insight into the origin and behaviour of aerosols in this zone and can be employed in situations in which one does not have local aerosol measurements. For this purpose, an aerosol spectrometer and dust monitor (Grimm 1.109) was installed at the Pierre Auger Observatory of ultra-high-energy cosmic rays, to record aerosol concentrations in different size intervals, at surface level. These measurements are analysed and correlated with air mass trajectories obtained from HYSPLIT (NOAA) model calculations. High aerosol concentrations are registered predominantly when air masses have travelled mostly over continental areas, mainly from the NE direction, while low aerosol concentrations are found in correspondence with air masses coming from the Pacific Ocean, from the NW direction. Different size distribution patterns were found for the aerosols depending on their origin: marine or continental. This work shows for the first time the size distribution of aerosols registered at the Pierre Auger Observatory. The correlations found between mass and particle concentrations (total and for different size ranges) and HYSPLIT air mass trajectories, confirm that the latter can be employed as a useful tool to infer the sources, evolution

AGE AND STRAIN INFLUENCES ON LUNG RESPONSES TO CONCENTRATED AIR PARTICULATES (CAPS) IN RODENTS

EPA Science Inventory

Asthma, an inflammatory airways disease, is an urgent health problem. Recent epidemiologic studies have demonstrated positive associations between ambient air particulate matter concentrations and daily respiratory morbidity ? including exacerbations of asthma. Of note, elderly i...

Quantifying the impact of current and future concentrations of air pollutants on respiratory disease risk in England.

PubMed

Pannullo, Francesca; Lee, Duncan; Neal, Lucy; Dalvi, Mohit; Agnew, Paul; O'Connor, Fiona M; Mukhopadhyay, Sabyasachi; Sahu, Sujit; Sarran, Christophe

2017-03-27

Estimating the long-term health impact of air pollution in a spatio-temporal ecological study requires representative concentrations of air pollutants to be constructed for each geographical unit and time period. Averaging concentrations in space and time is commonly carried out, but little is known about how robust the estimated health effects are to different aggregation functions. A second under researched question is what impact air pollution is likely to have in the future. We conducted a study for England between 2007 and 2011, investigating the relationship between respiratory hospital admissions and different pollutants: nitrogen dioxide (NO 2 ); ozone (O 3 ); particulate matter, the latter including particles with an aerodynamic diameter less than 2.5 micrometers (PM 2.5 ), and less than 10 micrometers (PM 10 ); and sulphur dioxide (SO 2 ). Bayesian Poisson regression models accounting for localised spatio-temporal autocorrelation were used to estimate the relative risks (RRs) of pollution on disease risk, and for each pollutant four representative concentrations were constructed using combinations of spatial and temporal averages and maximums. The estimated RRs were then used to make projections of the numbers of likely respiratory hospital admissions in the 2050s attributable to air pollution, based on emission projections from a number of Representative Concentration Pathways (RCP). NO 2 exhibited the largest association with respiratory hospital admissions out of the pollutants considered, with estimated increased risks of between 0.9 and 1.6% for a one standard deviation increase in concentrations. In the future the projected numbers of respiratory hospital admissions attributable to NO 2 in the 2050s are lower than present day rates under 3 Representative Concentration Pathways (RCPs): 2.6, 6.0, and 8.5, which is due to projected reductions in future NO 2 emissions and concentrations. NO 2 concentrations exhibit consistent substantial present

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

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

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)more » 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.« less

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

Studying the location of SACs and DACs regions in the environment of hot emission stars

NASA Astrophysics Data System (ADS)

Antoniou, A.; Danezis, E.; Lyratzi, E.; Popović, L. Č.; Dimitrijević, M. S.; Theodossiou, E.

Hot emission stars (Oe and Be stars) present complex spectral line profiles, which are formed by a number of DACs and/or SACs. In order to explain and reproduce theoretically these complex line profiles we use the GR model (Gauss-Rotation model). This model presupposes that the regions, where the spectral lines are created, consist of a number of independent and successive absorbing or emitting density regions of matter. Here we are testing a new approach of the GR model, which supposes that the independent density regions are not successive. We use this new approach in the spectral lines of some Oe and Be stars and we compare the results of this method with the results deriving from the classical GR model that supposes successive regions.

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

2015-10-06

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.

Two dimensional numerical analysis of aerodynamic characteristics for rotating cylinder on concentrated air flow

NASA Astrophysics Data System (ADS)

Alias, M. S.; Rafie, A. S. Mohd; Marzuki, O. F.; Hamid, M. F. Abdul; Chia, C. C.

2017-12-01

Over the years, many studies have demonstrated the feasibility of the Magnus effect on spinning cylinder to improve lift production, which can be much higher than the traditional airfoil shape. With this characteristic, spinning cylinder might be used as a lifting device for short take-off distance aircraft or unmanned aerial vehicle (UAV). Nonetheless, there is still a gap in research to explain the use of spinning cylinder as a good lifting device. Computational method is used for this study to analyse the Magnus effect, in which two-dimensional finite element numerical analysis method is applied using ANSYS FLUENT software to examine the coefficients of lift and drag, and to investigate the flow field around the rotating cylinder surface body. Cylinder size of 30mm is chosen and several configurations in steady and concentrated air flows have been evaluated. All in all, it can be concluded that, with the right configuration of the concentrated air flow setup, the rotating cylinder can be used as a lifting device for very short take-off since it can produce very high coefficient of lift (2.5 times higher) compared with steady air flow configuration.

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.

Relevance of air conditioning for 222Radon concentration in shops of the Savona Province, Italy.

PubMed

Panatto, Donatella; Ferrari, Paola; Lai, Piero; Gallelli, Giovanni

2006-02-15

Radon (222Rn) concentration was evaluated in shops of the Savona Province, Italy, between summer 2002 and winter 2002-2003. The main characteristics of each shops were recorded through a questionnaire investigating the ventilation rate and factors related to 222Rn precursors in the soil and the construction materials. The main variables that were related to radon concentration were the following: age of the building, level of the shop above ground, season of the year, wind exposure, active windows, and type of heating system. Shops equipped with individual air heating/conditioning systems exhibited radon concentrations that were three times higher than those of shops heated by centralized furnaces. Our data indicate that the level of pollution in the shops was of medium level, with an expected low impact on the salespersons' health. Only in wintertime, the action level of 200 Bq m(-3) for the confined environment was reached in 10 shops equipped with individual air heating/conditioning systems.

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...

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

Cross-validation of the osmotic pressure based on Pitzer model with air humidity osmometry at high concentration of ammonium sulfate solutions.

PubMed

Wang, Xiao-Lan; Zhan, Ting-Ting; Zhan, Xian-Cheng; Tan, Xiao-Ying; Qu, Xiao-You; Wang, Xin-Yue; Li, Cheng-Rong

2014-01-01

The osmotic pressure of ammonium sulfate solutions has been measured by the well-established freezing point osmometry in dilute solutions and we recently reported air humidity osmometry in a much wider range of concentration. Air humidity osmometry cross-validated the theoretical calculations of osmotic pressure based on the Pitzer model at high concentrations by two one-sided test (TOST) of equivalence with multiple testing corrections, where no other experimental method could serve as a reference for comparison. Although more strict equivalence criteria were established between the measurements of freezing point osmometry and the calculations based on the Pitzer model at low concentration, air humidity osmometry is the only currently available osmometry applicable to high concentration, serves as an economic addition to standard osmometry.

Concentrations of Staphylococcus species in indoor air as associated with other bacteria, season, relative humidity, air change rate, and S. aureus-positive occupants.

PubMed

Madsen, Anne Mette; Moslehi-Jenabian, Saloomeh; Islam, Md Zohorul; Frankel, Mika; Spilak, Michal; Frederiksen, Margit W

2018-01-01

The aim of this study was to obtain knowledge about concentrations of Staphylococcus aureus, MRSA (methicillin-resistant S. aureus), and other Staphylococcus species in indoor air in Greater Copenhagen and about factors affecting the concentrations. The effects of season, temperature, relative humidity, air change rate (ACR), other bacterial genera, area per occupant, and presence of S. aureus-positive occupants were studied. In samples from 67 living rooms, S. hominis, S. warneri, S. epidermidis, and S. capitis were found in 13-25%; S. saprophyticus, S. cohnii, and S. pasteuri in 5-10%; and S. lugdunensis, S. haemolyticus, S. caprae, S. equorum, S. kloosii, S. pettenkoferi, S. simulans, and S. xylosus in less than 3%. Staphylococcus aureus were found in two of 67 living rooms: spa type t034 (an MRSA) was recovered from a farmhouse, while spa type t509 was found in an urban home. Two species, S. equorum and S. kloosii, were found only in the farmhouse. Staphylococcus was significantly associated with season with lowest concentration and richness in winter. Genera composition was associated with ACR with smaller fractions of Staphylococcus at higher ACR, while richness was significantly and negatively associated with area per occupant. Concentration of Staphylococcus correlated positively with the total concentration of bacteria, but negatively with the total concentration of other bacteria. The concentration of Staphylococcus was not significantly associated with concentrations of the other abundant genera Bacillus, Kocuria, and Micrococcus. In offices with S. aureus-positive occupants, airborne S. aureus was not found. In conclusion, Staphylococcus species constitute a considerable proportion of the airborne bacteria in the studied homes and offices. However, both S. aureus and MRSA had very low prevalence during all seasons. Thus, transmission of S. aureus and MRSA through the air in living rooms in Copenhagen is expected to be limited. The negative associations

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

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).

Reducing the oxygen concentration of gases delivered from anaesthetic machines unadapted for medical air

PubMed Central

Clutton, R. E.; Schoeffmann, G.; Chesnil, M.; Gregson, R.; Reed, F.; Lawson, H.; Eddleston, M.

2014-01-01

High fractional concentrations of inspired oxygen (FiO2) delivered over prolonged periods produce characteristic histological changes in the lungs and airway of exposed animals. Modern medical anaesthetic machines are adapted to deliver medical air (FiO2=0.21) for the purpose of reducing FiO2; anaesthetic machines designed for the veterinary market have not been so adapted. Two inexpensive modifications that allow medical air to be added to the gas flow from veterinary anaesthetic machines are described. The advantages and disadvantages of each modification are discussed. PMID:21862470

Air pollution and associated human mortality: the role of air pollutant emissions, climate change and methane concentration increases from the preindustrial period to present

NASA Astrophysics Data System (ADS)

Fang, Y.; Naik, V.; Horowitz, L. W.; Mauzerall, D. L.

2013-02-01

Increases in surface ozone (O3) and fine particulate matter (≤2.5 μm aerodynamic diameter, PM2.5) are associated with excess premature human mortalities. We estimate changes in surface O3 and PM2.5 from pre-industrial (1860) to present (2000) and the global present-day (2000) premature human mortalities associated with these changes. We extend previous work to differentiate the contribution of changes in three factors: emissions of short-lived air pollutants, climate change, and increased methane (CH4) concentrations, to air pollution levels and 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 (results reported as annual average ±standard deviation of 10-yr model simulations), 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 population-weighted average PM2.5 (O35) 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 0.04 ± 0.24 μg m-3 (+4.3 ± 0.33 ppbv), respectively. Total global changes in PM2.5 are associated with 1.5 (95% confidence interval, CI, 1.2-1.8) million cardiopulmonary mortalities and 95 (95% CI, 44-144) thousand lung cancer mortalities annually and changes 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

Daily variation in fine and ultrafine particulate air pollution and urinary concentrations of lung Clara cell protein CC16

PubMed Central

Timonen, K; Hoek, G; Heinrich, J; Bernard, A; Brunekreef, B; de Hartog, J; Hameri, K; Ibald-Mulli, A; Mirme, A; Peters, A; Tiittanen, P; Kreyling, W; Pekkanen, J

2004-01-01

Background: Daily variations in ambient particulate air pollution have been associated with respiratory mortality and morbidity. Aims: To assess the associations between urinary concentration of lung Clara cell protein CC16, a marker for lung damage, and daily variation in fine and ultrafine particulate air pollution. Methods: Spot urinary samples (n = 1249) were collected biweekly for six months in subjects with coronary heart disease in Amsterdam, Netherlands (n = 37), Erfurt, Germany (n = 47), and Helsinki, Finland (n = 47). Ambient particulate air pollution was monitored at a central site in each city. Results: The mean 24 hour number concentration of ultrafine particles was 17.3x103 cm–3 in Amsterdam, 21.1x103 cm–3 in Erfurt, and 17.0x103 cm–3 in Helsinki. The mean 24 hour PM2.5 concentrations were 20, 23, and 13 µg/m3, respectively. Daily variation in ultrafine particle levels was not associated with CC16. In contrast, CC16 concentration seemed to increase with increasing levels of PM2.5 in Helsinki, especially among subjects with lung disorders. No clear associations were observed in Amsterdam and Erfurt. In Helsinki, the CC16 concentration increased by 20.2% (95% CI 6.9 to 33.5) per 10 µg/m3 increase in PM2.5 concentration (lag 2). The respective pooled effect estimate was 2.1% (95% CI –1.3 to 5.6). Conclusion: The results suggest that exposure to particulate air pollution may lead to increased epithelial barrier permeability in lungs. PMID:15477284

Health benefits of air pollution abatement policy: Role of the shape of the concentration-response function.

PubMed

Pope, C Arden; Cropper, Maureen; Coggins, Jay; Cohen, Aaron

2015-05-01

There is strong evidence that fine particulate matter (aerodynamic diameter<2.5 μm; PM2.5) air pollution contributes to increased risk of disease and death. Estimates of the burden of disease attributable to PM2.5 pollution and benefits of reducing pollution are dependent upon the shape of the concentration response (C-R) functions. Recent evidence suggests that the C-R function between PM2.5 air pollution and mortality risk may be supralinear across wide ranges of exposure. Such results imply that incremental pollution abatement efforts may yield greater benefits in relatively clean areas than in highly polluted areas. The role of the shape of the C-R function in evaluating and understanding the costs and health benefits of air pollution abatement policy is explored. There remain uncertainties regarding the shape of the C-R function, and additional efforts to more fully understand the C-R relationships between PM2.5 and adverse health effects are needed to allow for more informed and effective air pollution abatement policies. Current evidence, however, suggests that there are benefits both from reducing air pollution in the more polluted areas and from continuing to reduce air pollution in cleaner areas. Estimates of the benefits of reducing PM2.5 air pollution are highly dependent upon the shape of the PM2.5-mortality concentration-response (C-R) function. Recent evidence indicates that this C-R function may be supralinear across wide ranges of exposure, suggesting that incremental pollution abatement efforts may yield greater benefits in relatively clean areas than in highly polluted areas. This paper explores the role of the shape of the C-R function in evaluating and understanding the costs and health benefits of PM2.5 air pollution abatement.

Key Factors Determining Indoor Air PM10 Concentrations in Naturally Ventilated Primary Schools in Belgrade, Serbia

PubMed Central

Matic, Branislava; Rakic, Uros; Jovanovic, Verica; Dejanovic, Snezana; Djonovic, Nela

2017-01-01

Abstract Introduction Indoor air quality (IAQ) is rated as a serious public health issue. Knowing children are accounted as more vulnerable to environmental health hazards, data are needed on air quality in schools. Methods A project was conducted from 2007 until 2009 (SEARCH, School Environment and Respiratory Health of Children), aiming to verify links between IAQ and children’s respiratory health. Study was conducted in ten primary schools on 735 children, in 44 classrooms. Children were randomly selected. Research tools and indicators used for children’s exposure to school environment were indoor and outdoor pollutants, two standardized questionnaires for school and classroom characteristics. In both classroom air and ambient air in front of them we measured, during a 5-day exposure period for continuous 24h measuring: carbon monoxide, carbon dioxide, indoor air temperature, relative humidity, and PM10 during classes. Results PM10 concentrations were significantly most frequent in an interval of ≥80.1μg/m3, that is, in the interval above 50μg/m3. Mean PM10 value was 82.24±42.43 μg/m3, ranging from 32.00μg/m3 to of 197.00μg/m3. Conclusion The increase of outdoor PM10 concentration significantly affects the increase of indoor PM10. A statistically significant difference exists for average IAQ PM10 concentrations vs. indicators of indoor thermal comfort zone (p<0.0001); they are lower in the classrooms with indicators within the comfort zone. Moreover, dominant factors for the increase of PM10 are: high occupancy rate in the classroom (<2m2 of space per child), high relative humidity (>75%), and indoor temperature beyond 23°C, as well as bad ventilation habits (keeping windows shut most of the time). PMID:29062397

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. © 2015 Her Majesty the Queen in Right of Canada. Indoor Air published by John Wiley & Sons Ltd. Reproduced with the permission of the Minister of Health Canada.

Atmospheric concentrations and air-soil gas exchange of polycyclic aromatic hydrocarbons (PAHs) in remote, rural village and urban areas of Beijing-Tianjin region, North China.

PubMed

Wang, Wentao; Simonich, Staci; Giri, Basant; Chang, Ying; Zhang, Yuguang; Jia, Yuling; Tao, Shu; Wang, Rong; Wang, Bin; Li, Wei; Cao, Jun; Lu, Xiaoxia

2011-07-01

Forty passive air samplers were deployed to study the occurrence of gas and particulate phase PAHs in remote, rural village and urban areas of Beijing-Tianjin region, North China for four seasons (spring, summer, fall and winter) from 2007 to 2008. The influence of emissions on the spatial distribution pattern of air PAH concentrations was addressed. In addition, the air-soil gas exchange of PAHs was studied using fugacity calculations. The median gaseous and particulate phase PAH concentrations were 222 ng/m³ and 114 ng/m³, respectively, with a median total PAH concentration of 349 ng/m³. Higher PAH concentrations were measured in winter than in other seasons. Air PAH concentrations measured at the rural villages and urban sites in the northern mountain region were significantly lower than those measured at sites in the southern plain during all seasons. However, there was no significant difference in PAH concentrations between the rural villages and urban sites in the northern and southern areas. This urban-rural PAH distribution pattern was related to the location of PAH emission sources and the population distribution. The location of PAH emission sources explained 56%-77% of the spatial variation in ambient air PAH concentrations. The annual median air-soil gas exchange flux of PAHs was 42.2 ng/m²/day from soil to air. Among the 15 PAHs measured, acenaphthylene (ACY) and acenaphthene (ACE) contributed to more than half of the total exchange flux. Furthermore, the air-soil gas exchange fluxes of PAHs at the urban sites were higher than those at the remote and rural sites. In summer, more gaseous PAHs volatilized from soil to air because of higher temperatures and increased rainfall. However, in winter, more gaseous PAHs deposited from air to soil due to higher PAH emissions and lower temperatures. The soil TOC concentration had no significant influence on the air-soil gas exchange of PAHs. Copyright © 2011 Elsevier B.V. All rights reserved.

Final Report for "Tech-X Corporation work for the SciDAC Center for Simulation of RF Wave Interactions with Magnetohydrodynamics (SWIM)"

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

Jenkins, Thomas G.; Kruger, Scott E.

Work carried out by Tech-X Corporation for the DoE SciDAC Center for Simulation of RF Wave Interactions with Magnetohydrodynamics (SWIM; U.S. DoE Office of Science Award Number DE-FC02-06ER54899) is summarized and is shown to fulfil the project objectives. The Tech-X portion of the SWIM work focused on the development of analytic and computational approaches to study neoclassical tearing modes and their interaction with injected electron cyclotron current drive. Using formalism developed by Hegna, Callen, and Ramos [Phys. Plasmas 16, 112501 (2009); Phys. Plasmas 17, 082502 (2010); Phys. Plasmas 18, 102506 (2011)], analytic approximations for the RF interaction were derived andmore » the numerical methods needed to implement these interactions in the NIMROD extended MHD code were developed. Using the SWIM IPS framework, NIMROD has successfully coupled to GENRAY, an RF ray tracing code; additionally, a numerical control system to trigger the RF injection, adjustment, and shutdown in response to tearing mode activity has been developed. We discuss these accomplishments, as well as prospects for ongoing future research that this work has enabled (which continue in a limited fashion under the SciDAC Center for Extended Magnetohydrodynamic Modeling (CEMM) project and under a baseline theory grant). Associated conference presentations, published articles, and publications in progress are also listed.« less

A Data Analysis Center for Electromagnetic and Hadronic Interaction. Products of the DAC members

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

Briscoe, William John; Strakovsky, Igor I.; Workman, Ronald L.

The Data Analysis Center (DAC) of the Center for Nuclear Studies (CNS) at the George Washington University (GW) has made significant progress in its program to enhance and expand the partial-wave (and multipole) analyses of fundamental two- and three-body reactions (such as pion-nucleon, photon-nucleon, and nucleon-nucleon scattering) by maintaining and augmenting the analysis codes and databases associated with these reactions. These efforts provide guidance to experimental groups at the international level, forming an important link between theory and experiment. A renaissance in light hadron spectroscopy is underway as a continuous stream of polarization data issues from existing precision electromagnetic facilitiesmore » and the coming Jefferson Lab 12 GeV Upgrade. Our principal goals have been focused on supporting the national N* resonance physics program. We have also continued to study topics more generally related to the problems associated with partial-wave analysis. On the Experimental side of the CNS DAC. Its primary goal is the enhancement of the body of data necessary for our analyses of fundamental γ - N reactions. We perform experiments that study the dynamics responsible for the internal structure of the nucleon and its excitations. Our principal focus is on the N* programs at JLab and MAMI. At JLab we study spin-polarization observables using polarized photons, protons and neutrons and yielding charged final states. Similarly at MAMI we study neutral meson photoproduction off polarized protons and neutrons. We use the Crystal Ball and TAPS spectrometers (CBT) to detect photons and neutrons to measure the photoproduction of π0, η, 2π0, π0η, and K0 off the neutron. The CBT program complements our program at JLab, which studies reactions resulting in charged final states. We are also involved in a renewed effort to make neutral pion photoproduction measurements close to threshold at Mainz. In addition to the programs underway, we are

High Concentrations of Ozone Air Pollution on Mount Everest: Health Implications for Sherpa Communities and Mountaineers.

PubMed

Semple, John L; Moore, G W Kent; Koutrakis, Petros; Wolfson, Jack M; Cristofanelli, Paolo; Bonasoni, Paolo

2016-12-01

Semple, John L., G.W. Kent Moore, Petros Koutrakis, Jack M. Wolfson, Paolo Cristofanelli, and Paolo Bonasoni. High concentrations of ozone air pollution on Mount Everest: health implications for Sherpa communities and mountaineers. High Alt Med Biol. 17:365-369, 2016.-Introduction: Populations in remote mountain regions are increasingly vulnerable to multiple climate mechanisms that influence levels of air pollution. Few studies have reported on climate-sensitive health outcomes unique to high altitude ecosystems. In this study, we report on the discovery of high-surface ozone concentrations and the potential impact on health outcomes on Mount Everest and the high Himalaya. Surface ozone measurements were collected during ascending transects in the Mount Everest region of Nepal with passive nitrite-coated Ogawa filter samplers to obtain 8-hour personal exposures (2860-5364 m asl). In addition, the Nepal Climate Observatory-Pyramid, a GAW-WMO Global Station sited in the Khumbu Valley (5079 m asl), collected ozone mixing ratios with photometric gas analyzer. Surface ozone measurements increased with altitude with concentrations that exceed 100 ppb (8-hour exposure). Highest values were during the spring season and the result of diverse contributions: hemispheric background values, the descent of ozone-rich stratospheric air, and the transport of tropospheric pollutants occurring at different spatial scales. Multiple climate factors, including descending stratospheric ozone and imported anthropogenic air masses from the Indo-Gangetic Plain, contribute to ambient ozone exposure levels in the vicinity of Mount Everest that are similar to if not higher than those reported in industrialized cities.

Impacts of anthropogenic emissions and cold air pools on urban to montane gradients of snowpack ion concentrations in the Wasatch Mountains, Utah

NASA Astrophysics Data System (ADS)

Hall, Steven J.; Maurer, Gregory; Hoch, Sebastian W.; Taylor, Raili; Bowling, David R.

2014-12-01

Urban montane valleys are often characterized by periodic wintertime temperature inversions (cold air pools) that increase atmospheric particulate matter concentrations, potentially stimulating the deposition of major ions to these snow-covered ecosystems. We assessed spatial and temporal patterns of ion concentrations in snow across urban to montane gradients in Salt Lake City, Utah, USA, and the adjacent Wasatch Mountains during January 2011, a period of several persistent cold air pools. Ion concentrations in fresh snow samples were greatest in urban sites, and were lower by factors of 4-130 in a remote high-elevation montane site. Adjacent undeveloped canyons experienced significant incursions of particulate-rich urban air during stable atmospheric conditions, where snow ion concentrations were lower but not significantly different from urban sites. Surface snow ion concentrations on elevation transects in and adjacent to Salt Lake City varied with temporal and spatial trends in aerosol concentrations, increasing following exposure to particulate-rich air as cold air pools developed, and peaking at intermediate elevations (1500-1600 m above sea level, or 200-300 m above the valley floor). Elevation trends in ion concentrations, especially NH4+ and NO3-, corresponded with patterns of aerosol exposure inferred from laser ceilometer data, suggesting that high particulate matter concentrations stimulated fog or dry ion deposition to snow-covered surfaces at the top of the cold air pools. Fog/dry deposition inputs were similar to wet deposition at mid-elevation montane sites, but appeared negligible at lower and higher-elevation sites. Overall, snow ion concentrations in our urban and adjacent montane sites exceeded many values reported from urban precipitation in North America, and greatly exceeded those reported for remote snowpacks. Sodium, Cl-, NH4+, and NO3- concentrations in fresh snow were high relative to previously measured urban precipitation, with means

Ada Compiler Validation Summary Report: Certificate Number: 940325S1. 11341 DDC-I, DACS Sun SPARC/SunOS to 80186 Bare Ada Cross Compiler System, Version 4.6.4 Sun SPARCstation IPX = Intel iSBC 186/100 (Bare Machine)

DTIC Science & Technology

1994-03-25

declarations requiring more digits than SYSTEM.MAXDIGITS: C24113L..Y (14 tests) C35705L..Y (14 tests) C35706L..Y (14 tests) C35707L..Y (14 tests) 2-1...before the DACS Run-Time System (RMs) libary normally searches for na-4ime routin;, in this way one can replace the standard DACS RTS routines with...SHORTINTEGER is range -128 .. 127; type INTEGER is range -32_768 .. 32_767; type LONGINTEGER is range -2147_483_648 .. 2_147_483_647; type FLOAT is digits 6

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.

Separation of malignant human breast cancer epithelial cells from healthy epithelial cells using an advanced dielectrophoresis-activated cell sorter (DACS).

PubMed

An, Jaemin; Lee, Jangwon; Lee, Sang Ho; Park, Jungyul; Kim, Byungkyu

2009-06-01

In this paper, we successfully separated malignant human breast cancer epithelial cells (MCF 7) from healthy breast cells (MCF 10A) and analyzed the main parameters that influence the separation efficiency with an advanced dielectrophoresis (DEP)-activated cell sorter (DACS). Using the efficient DACS, the malignant cancer cells (MCF 7) were isolated successfully by noninvasive methods from normal cells with similar cell size distributions (MCF 10A), depending on differences between their material properties such as conductivity and permittivity, because our system was able to discern the subtle differences in the properties by generating continuously changed electrical field gradients. In order to evaluate the separation performance without considering size variations, the cells collected from each outlet were divided into size-dependent groups and counted statistically. Following that, the quantitative relative ratio of numbers between MCF 7 and MCF 10A cells in each size-dependent group separated by the DEP were compared according to applied frequencies in the range 48, 51, and 53 MHz with an applied amplitude of 8 V(pp). Finally, under the applied voltage of 48 MHz-8 V(pp) and a flow rate of 290 microm/s, MCF 7 and MCF 10A cells were separated with a maximum efficiency of 86.67% and 98.73% respectively. Therefore, our suggested system shows it can be used for detection and separation of cancerous epithelial cells from noncancerous cells in clinical applications.

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

Cleaning products and air fresheners: emissions and resulting concentrations of glycol ethers and terpenoids.

PubMed

Singer, B C; Destaillats, H; Hodgson, A T; Nazaroff, W W

2006-06-01

Experiments were conducted to quantify emissions and concentrations of glycol ethers and terpenoids from cleaning product and air freshener use in a 50-m3 room ventilated at approximately 0.5/h. 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 microg/m3 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 d-limonene were 300-6000 microg/m3 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, and approximately 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 approximately 35-70% with towels retained, and 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/day over 3 days while air concentrations averaged 30-160 microg/m3. While effective cleaning can improve the healthfulness of indoor environments, this work shows that use of some consumer cleaning agents can yield high levels of volatile organic compounds, including glycol ethers--which are regulated toxic air contaminants--and terpenes that can react with ozone to form a variety of secondary pollutants including formaldehyde and ultrafine particles. Persons involved in cleaning, especially those who clean occupationally or often, might encounter

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.

Xi Per [O7.5 III(n)((f))]: DACs, NRPs and Now Co-rotating Hot Spots with MOST

NASA Astrophysics Data System (ADS)

Ramiaramanantsoa, Tahina; Moffat, A.; Chene, A.-N.; Desforges, S.; Henrichs, H.; MOST Science Team

2013-06-01

We have used the MOST (Microvariability and Oscillations of Stars) microsatellite to obtain four weeks of contiguous high-precision broadband visual photometry in Nov 2011 along with several simultaneous nights of ground-based medium-resolution high signal-to-noise optical spectroscopic monitoring of the O7.5III star xi Persei. This star is well known from previous work to show prominent DACs (Discrete Absorption Components) on times-scales of about two days from UV spectroscopy and NRP (Non Radial Pulsation) with one (l=3) p-mode oscillation of period 3.5 hours from optical spectroscopy. Our MOST-orbit (101 min) binned photometry fails to reveal any coherent pulsations above the 0.1 mmag 3-sigma noise level for periods of hours, while several prominent Fourier peaks emerge at the 1 mmag level in the two-day period range. These longer-period variations are unlikely due to pulsations; rather we deduce from our simulations based upon a simple spot model that we are seeing the photometric modulation of several co-rotating hot spots on the stellar surface, whose lifetimes vary yet they all rotate at the same (probable) period of 4 days, i.e. the best-estimated stellar rotation period. We are in the process of examining if our new optical spectra at a cadence of ~ 5 minutes and signal-to-noise ~ 150 reveal any periodicities on hour and day timescales. This may be the first reported case of co-rotating hot spots on an O star, with important implications for drivers of the DACs (resulting from CIRs, Corotating Interaction Regions) and possible generation via a subsurface convection zone.

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...

Assessment of workplace air concentrations of formaldehyde during and before working hours in medical facilities.

PubMed

Higashikubo, Ichiro; Miyauchi, Hiroyuki; Yoshida, Satoru; Tanaka, Shinsuke; Matsuoka, Mitsunori; Arito, Heihachiro; Araki, Akihiro; Shimizu, Hidesuke; Sakurai, Haruhiko

2017-04-07

Workplace air concentrations of formaldehyde (FA) in medical facilities where FA and FA-treated organs were stored and handled were measured before and during working hours and assessed by the official method specified by Work Environment Measurement Law. Sixty-percent of the total facilities examined were judged as inappropriately controlled work environment. The concentrations of FA before working hours by spot sampling were found to exceed 0.1 ppm in some facilities, and tended to increase with increasing volume of containers storing FA and FA-treated materials. Regression analysis revealed that logarithmic concentrations of FA during working hours by the Law-specified analytical method were highly correlated with those before working hours by spot sampling, suggesting the importance for appropriate storing methods of FA and FA-treated materials. The concentrations of FA during working hours are considered to be lowered by effective ventilation of FA-contaminated workplace air and appropriate storage of FA and FA-treated materials in plastic containers in the medical facilities. In particular, such improvement by a local exhaust ventilation system and tightly-sealed containment of FA-treated material were urgently needed for the dissecting room where FA-treated cadavers were prepared and handled for a gross anatomy course in a medical school.

Analytical solutions to compartmental indoor air quality models with application to environmental tobacco smoke concentrations measured in a house.

PubMed

Ott, Wayne R; Klepeis, Neil E; Switzer, Paul

2003-08-01

This paper derives the analytical solutions to multi-compartment indoor air quality models for predicting indoor air pollutant concentrations in the home and evaluates the solutions using experimental measurements in the rooms of a single-story residence. The model uses Laplace transform methods to solve the mass balance equations for two interconnected compartments, obtaining analytical solutions that can be applied without a computer. Environmental tobacco smoke (ETS) sources such as the cigarette typically emit pollutants for relatively short times (7-11 min) and are represented mathematically by a "rectangular" source emission time function, or approximated by a short-duration source called an "impulse" time function. Other time-varying indoor sources also can be represented by Laplace transforms. The two-compartment model is more complicated than the single-compartment model and has more parameters, including the cigarette or combustion source emission rate as a function of time, room volumes, compartmental air change rates, and interzonal air flow factors expressed as dimensionless ratios. This paper provides analytical solutions for the impulse, step (Heaviside), and rectangular source emission time functions. It evaluates the indoor model in an unoccupied two-bedroom home using cigars and cigarettes as sources with continuous measurements of carbon monoxide (CO), respirable suspended particles (RSP), and particulate polycyclic aromatic hydrocarbons (PPAH). Fine particle mass concentrations (RSP or PM3.5) are measured using real-time monitors. In our experiments, simultaneous measurements of concentrations at three heights in a bedroom confirm an important assumption of the model-spatial uniformity of mixing. The parameter values of the two-compartment model were obtained using a "grid search" optimization method, and the predicted solutions agreed well with the measured concentration time series in the rooms of the home. The door and window positions in

Determination of Fluorine in Fluoro-Organic Compounds in Low Concentrations in Air

DTIC Science & Technology

1944-06-27

Analysis of 2-Fluoroethanol in Air ..... SUMMARY BIBLIOGRAPHY 15 APPENDIX , 16 FIGURE 1 Apparatus PLATE 1 CDS Scrubber SECRET ) SECRET...liter, and 68$ at 1 - 2 mg. per liter. By using two scrubbers in series, 90$ of di-isopropyl fluorophosphate was recovered at a concentration of 1 to 2...chromic acid and detection of HP by etching of the glass container ; (5) scrub- bing the gas with ammonia and decomposing the fluoro-organic compound4

Air concentrations of /sup 239/Pu and /sup 240/Pu and potential radiation doses to persons living near Pu-contaminated areas in Palomares, Spain

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

Iranzo, E.; Salvador, S.; Iranzo, C.E.

1987-04-01

On 17 January 1966, an accident during a refueling operation resulted in the destruction of an air force KC-135 tanker and a B-52 bomber carrying four thermonuclear weapons. Two weapons, whose parachutes opened, were found intact. The others experienced non-nuclear explosion with some burning and release of the fissile fuel at impact. Joint efforts by the United States and Spain resulted in remedial action and a long-term program to monitor the effectiveness of the cleanup. Air concentrations of /sup 239/Pu and /sup 240/Pu have been continuously monitored since the accident. The average annual air concentration for each location was usedmore » to estimate committed dose equivalents for individuals living and working around the air sampling stations. The average annual /sup 239/Pu and /sup 240/Pu air concentrations during the 15-y period corresponding to 1966-1980 and the potential committed dose equivalents for various tissues due to the inhalation of the /sup 239/Pu and /sup 240/Pu average annual air concentration during this period are shown and discussed in the report.« less

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 ...

Influence of wind-induced air pressure fluctuations on topsoil gas concentrations within a Scots pine forest

NASA Astrophysics Data System (ADS)

Mohr, Manuel; Laemmel, Thomas; Maier, Martin; Schindler, Dirk

2017-04-01

Commonly it is assumed that soil gas transport is dominated by molecular diffusion. Few recent studies indicate that the atmosphere above the soil triggers non-diffusive gas transport processes in the soil, which can enhance soil gas transport and therefore soil gas efflux significantly. During high wind speed conditions, the so called pressure pumping effect has been observed: the enhancement of soil gas transport through dynamic changes in the air pressure field above the soil. However, the amplitudes and frequencies of the air pressure fluctuations responsible for pressure pumping are still uncertain. Moreover, an in situ observation of the pressure pumping effect is still missing. To investigate the pressure pumping effect, airflow measurements above and below the canopy of a Scots pine forest and high-precision relative air pressure measurements were conducted in the below-canopy space and in the soil over a measurement period of 16 weeks. To monitor the soil gas transport, a newly developed gas measurement system was used. The gas measurement system continuously injects helium as a tracer gas into the soil until a diffusive steady state is reached. With the steady state concentration profile of the tracer gas, it is possible to inversely model the gas diffusion coefficient profile of the soil. If the gas diffusion coefficient profile differed from steady state, we deduced that the soil gas transport is not only diffusive, but also influenced by non-diffusive processes. Results show that the occurrence of small air pressure fluctuations is strongly dependent on the mean above-canopy wind speed. The wind-induced air pressure fluctuations have mean amplitudes up to 10 Pa and lie in the frequency range 0.01-0.1 Hz. To describe the pumping motion of the air pressure field, the pressure pumping coefficient (PPC) was defined as the mean change in pressure per second. The PPC shows a clear quadratic dependence on mean above-canopy wind speed. Empirical modelling of

High-Thermal- and Air-Stability Cathode Material with Concentration-Gradient Buffer for Li-Ion Batteries.

PubMed

Shi, Ji-Lei; Qi, Ran; Zhang, Xu-Dong; Wang, Peng-Fei; Fu, Wei-Gui; Yin, Ya-Xia; Xu, Jian; Wan, Li-Jun; Guo, Yu-Guo

2017-12-13

Delivery of high capacity with high thermal and air stability is a great challenge in the development of Ni-rich layered cathodes for commercialized Li-ion batteries (LIBs). Herein we present a surface concentration-gradient spherical particle with varying elemental composition from the outer end LiNi 1/3 Co 1/3 Mn 1/3 O 2 (NCM) to the inner end LiNi 0.8 Co 0.15 Al 0.05 O 2 (NCA). This cathode material with the merit of NCM concentration-gradient protective buffer and the inner NCA core shows high capacity retention of 99.8% after 200 cycles at 0.5 C. Furthermore, this cathode material exhibits much improved thermal and air stability compared with bare NCA. These results provide new insights into the structural design of high-performance cathodes with high energy density, long life span, and storage stability materials for LIBs in the future.

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.

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...

A Comparative Study of Three Spatial Interpolation Methodologies for the Analysis of Air Pollution Concentrations in Athens, Greece

NASA Astrophysics Data System (ADS)

Deligiorgi, Despina; Philippopoulos, Kostas; Thanou, Lelouda; Karvounis, Georgios

2010-01-01

Spatial interpolation in air pollution modeling is the procedure for estimating ambient air pollution concentrations at unmonitored locations based on available observations. The selection of the appropriate methodology is based on the nature and the quality of the interpolated data. In this paper, an assessment of three widely used interpolation methodologies is undertaken in order to estimate the errors involved. For this purpose, air quality data from January 2001 to December 2005, from a network of seventeen monitoring stations, operating at the greater area of Athens in Greece, are used. The Nearest Neighbor and the Liner schemes were applied to the mean hourly observations, while the Inverse Distance Weighted (IDW) method to the mean monthly concentrations. The discrepancies of the estimated and measured values are assessed for every station and pollutant, using the correlation coefficient, the scatter diagrams and the statistical residuals. The capability of the methods to estimate air quality data in an area with multiple land-use types and pollution sources, such as Athens, is discussed.

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.

Effect of biomass open burning on particulate matter and polycyclic aromatic hydrocarbon concentration levels and PAH dry deposition in ambient air.

PubMed

Chiu, Jui C; Shen, Yun H; Li, Hsing W; Chang, Shun S; Wang, Lin C; Chang-Chien, Guo P

2011-01-01

The objectives of the present study were to investigate particulate matter (PM) and polycyclic aromatic hydrocarbon (PAH) concentrations in ambient air during rice straw open burning and non-open burning periods. In the ambient air of a rice field, the mean PM concentration during and after an open burning event were 1828 and 102 μg m⁻³, respectively, which demonstrates that during a rice field open burning event, the PM concentration in the ambient air of rice field is over 17 times higher than that of the non-open burning period. During an open burning event, the mean total PAH and total toxic equivalence (BaP(eq)) concentrations in the ambient air of a rice field were 7206 ng m⁻³ and 10.3 ng m⁻³, respectively, whereas after the open burning event, they were 376 ng m⁻³ and 1.50 ng m⁻³, respectively. Open burning thus increases total PAH and total BaP(eq) concentrations by 19-fold and 6.8-fold, respectively. During a rice straw open burning event, in the ambient air of a rice field, the mean dry deposition fluxes of total PAHs and total BaP(eq) were 1222 μg m⁻² day⁻¹ and 4.80 μg m⁻² day⁻¹, respectively, which are approximately 60- and 3-fold higher than those during the non-open burning period, respectively. During the non-open burning period, particle-bound PAHs contributed 79.2-84.2% of total dry deposition fluxes (gas + particle) of total PAHs. However, an open burning event increases the contribution to total PAH dry deposition by particle-bound PAHs by up to 85.9-95.5%. The results show that due to the increased amount of PM in the ambient air resulting from rice straw open burning, particle-bound PAHs contributed more to dry deposition fluxes of total PAHs than they do during non-open burning periods. The results show that biomass (rice straw) open burning is an important PAH emission source that significantly increases both PM and PAH concentration levels and PAH dry deposition in ambient air.

Penicillin-binding protein 4 of Escherichia coli: molecular cloning of the dacB gene, controlled overexpression, and alterations in murein composition.

PubMed

Korat, B; Mottl, H; Keck, W

1991-03-01

The penicillin-binding protein 4 (PBP4), from Escherichia coli, a DD-carboxypeptidase/DD-endopeptidase, was purified in an enzymatically active form to homogeneity by affinity chromatography on 6-aminopenicillanic acid/Sepharose and heparin/Sepharose. Polyclonal antibodies raised against the pure protein were used to identify and isolate PBP4 overproducing clones from an E. coli expression library, which was established on the basis of a temperature-inducible runaway replication plasmid. Three positive clones were isolated, one of which carried the intact structural gene dacB that codes for PBP4, on a 1.9kb SmaI-EcoRI fragment, whereas the other two carried truncated forms of this gene. The direction of transcription was determined. The PBP4 overproducing strain, when grown in rich medium, tolerated 160-fold overexpression. After disrupting cells by sonication, the majority (80%) of the overproduced PBP4 was detected in the 100,000 X g supernatant. Southern blotting analysis using the cloned dacB gene as a probe revealed that, in contrast to that described by Takeda et al. (1981), the plasmid pLC18-38 of the Clarke-Carbon collection does not code for PBP4. The overall composition of murein, synthesized in vitro or in vivo by the PBP4 overproducing strain, as determined by high-performance liquid chromatography analysis, suggests that PBP4 is not involved in transpeptidation but exclusively catalyses a DD-carboxypeptidase and DD-endopeptidase reaction.

Numerical Investigation of the Flow Angularity Effects of the NASA Langley UPWT on the Ares I DAC1 0.01-Scale Model

NASA Technical Reports Server (NTRS)

Lee, Henry C.; Klopfer, Goetz H.; Onufer, Jeff T.

2011-01-01

Investigation of the non-uniform flow angularity effects on the Ares I DAC-1 in the Langley Unitary Plan Wind Tunnel are explored through simulations by OVERFLOW. Verification of the wind tunnel results are needed to ensure that the standard wind tunnel calibration procedures for large models are valid. The expectation is that the systematic error can be quantified, and thus be used to correct the wind tunnel data. The corrected wind tunnel data can then be used to quantify the CFD uncertainties.

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.

A complexity measure based method for studying the dependance of 222Rn concentration time series on indoor air temperature and humidity.

PubMed

Mihailovic, D T; Udovičić, V; Krmar, M; Arsenić, I

2014-02-01

We have suggested a complexity measure based method for studying the dependence of measured (222)Rn concentration time series on indoor air temperature and humidity. This method is based on the Kolmogorov complexity (KL). We have introduced (i) the sequence of the KL, (ii) the Kolmogorov complexity highest value in the sequence (KLM) and (iii) the KL of the product of time series. The noticed loss of the KLM complexity of (222)Rn concentration time series can be attributed to the indoor air humidity that keeps the radon daughters in air. © 2013 Published by Elsevier Ltd.

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Monitoring total endotoxin and (1 --> 3)-beta-D-glucan at the air exhaust of concentrated animal feeding operations.

PubMed

Yang, Xufei; Wang, Xinlei; Zhang, Yuanhui; Lee, Jongmin; Su, Jingwei; Gates, Richard S

2013-10-01

Mitigation of bioaerosol emissions from concentrated animal feeding operations (CAFOs) demands knowledge of bioaerosol concentrations feeding into an end-of-pipe air treatment process. The aim of this preliminary study was to measure total endotoxin and (1 --> 3)-beta-glucan concentrations at the air exhaust of 18 commercial CAFOs and to examine their variability with animal operation type (swine farrowing, swine gestation, swine weaning, swine finishing, manure belt laying hen, and tom turkey) and season (cold, mild, and hot). The measured airborne concentrations of total endotoxin ranged from 98 to 23,157 endotoxin units (EU)/m3, and the airborne concentrations of total (1 --> 3)-beta-D-glucan ranged from 2.4 to 537.9 ng/m3. Animal operation type in this study had a significant effect on airborne concentrations of total endotoxin and (1 --> 3)-beta-D-glucan but no significant effect on their concentrations in total suspended particulate (TSP). Both endotoxin and (1 --> 3)-beta-D-glucan attained their highest airborne concentrations in visited tom turkey buildings. Comparatively, season had no significant effect on airborne concentrations of total endotoxin or (1 --> 3)-beta-D-glucan. Endotoxin and (1 --> 3)-beta-glucan concentrations in TSP dust appeared to increase as the weather became warmer, and this seasonal effect was significant in swine buildings. Elevated indoor temperatures in the hot season were considered to facilitate the growth and propagation of bacteria and fungi, thus leading to higher biocomponent concentrations in TSP.

Biofiltration of air polluted with methane at concentration levels similar to swine slurry emissions: influence of ammonium concentration.

PubMed

Veillette, Marc; Avalos Ramirez, Antonio; Heitz, Michèle

2012-01-01

An evaluation of the effect of ammonium on the performance of two up-flow inorganic packed bed biofilters treating methane was conducted. The air flow rate was set to 3.0 L min(-1) for an empty bed residence time of 6.0 min. The biofilter was fed with a methane concentration of 0.30% (v/v). The ammonium concentration in the nutrient solution was increased by small increments (from 0.01 to 0.025 gN-NH(4) (+) L(-1)) for one biofilter and by large increments of 0.05 gN-NH(4) (+) L(-1) in the other biofilter. The total concentration of nitrogen was kept constant at 0.5 gN-NH(4) (+) L(-1) throughout the experiment by balancing ammonium with nitrate. For both biofilters, the methane elimination capacity, carbon dioxide production, nitrogen bed retention and biomass content decreased with the ammonium concentration in the nutrient solution. The biofilter with smaller ammonium increments featured a higher elimination capacity and carbon dioxide production rate, which varied from 4.9 to 14.3 g m(-3) h(-1) and from 11.5 to 30 g m(-3) h(-1), respectively. Denitrification was observed as some values of the nitrate production rate were negative for ammonium concentrations below 0.2 gN-NH(4) (+) L(-1). A Michalelis-Menten-type model fitted the ammonium elimination rate and the nitrate production rate.

Enhanced Adsorption Efficiency through Materials Design for Direct Air Capture over Supported Polyethylenimine.

PubMed

Sayari, Abdelhamid; Liu, Qing; Mishra, Prashant

2016-10-06

Until recently, carbon capture and sequestration (CCS) was regarded as the most promising technology to address the alarming increase in the concentration of anthropogenic CO 2 in the atmosphere. There is now an increasing interest in carbon capture and utilization (CCU). In this context, the capture of CO 2 from air is an ideal solution to supply pure CO 2 wherever it is needed. Here, we describe innovative materials for direct air capture (DAC) with unprecedented efficiency. Polyethylenimine (PEI) was supported on PME, which is an extra-large-pore silica (pore-expanded MCM-41) with its internal surfaces fully covered by a uniform layer of readily accessible C 16 chains from cetyltrimethylammonium (CTMA + ) cations. The CTMA + layer plays a key role in enhancing the amine efficiency toward dry or humid ultradilute CO 2 (400 ppm CO 2 /N 2 ) to unprecedented levels. At the same PEI content, the amine efficiency of PEI/PME was two to four times higher than that of the corresponding calcined mesoporous silica loaded with PEI or with different combinations of C 16 chains and PEI. Under humid conditions, the amine efficiency of 40 wt % PEI/PME reached 7.31 mmolCO2 /g PEI , the highest ever reported for any supported PEI in the presence of 400 ppm CO 2 . Thus, amine accessibility, which reflects both the state of PEI dispersion and the adsorption efficiency, is intimately associated with the molecular design of the adsorbent. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Elemental concentrations in tropospheric and lower stratospheric air in a Northeastern region of Poland

NASA Astrophysics Data System (ADS)

Braziewicz, Janusz; Kownacka, Ludwika; Majewska, Urszula; Korman, Andrzej

Element concentrations of K, Ca, Ti, Cr, Fe, Ni, Cu, Zn, Se, Br, Sr and Pb as well as the activity of natural radionuclides 210Pb and 226Ra in air were measured. The aerosol samples were collected during tropospheric and stratospheric aircraft flights over the Northeastern region of Poland, which is mostly an agricultural and wooded area. The air volumes were filtered using Petrianov filters at 1, 3, 6, 9, 12 and 15 km above the ground level by special equipment attached to a jet plane. Aircraft flights were provided from September 1997 to August 1998 in 5 separate sampling runs. The long sampling distances served as a good representation of mean aerosol composition and distribution. Concentrations of the same elements were also measured using stationary equipment near the ground level at the outskirts of Warsaw. The vertical profiles of element concentration were obtained and the elemental compositions for the tropospheric and stratospheric aerosols were compared with those from the near-ground level. Contribution of K, Ca, Ti and Fe, which are the main components of soil, in total mass of all detected ones was estimated. Relative concentrations of all measured elements, which show any differences in the composition of the aerosol were calculated. The results obtained confirm the fact that the stratospheric reservoir is observed in the bottom stratosphere. The XRF method based on molybdenum X-ray tube was used as an analytical tool in the determination of aerosols trace elements. The altitude distributions of radioactivity of 226Ra and 210Pb were determined using radiochemical methods.

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.

Rotational coherent anti-stokes Raman spectroscopy measurements in a rotating cavity with axial throughflow of cooling air: oxygen concentration measurements.

PubMed

Black, J D; Long, C A

1992-07-20

In a rotating cavity rig, which models cooling air flow in the spaces between disks of a gas turbine compressor, the buildup of oxygen concentration after the cooling gas was changed from nitrogen to air was monitored using rotational coherent anti-Stokes Raman spectroscopy (CARS). From this information an estimate of the fraction of the throughflow entering the rotating cavity was obtained. This demonstrates that rotational CARS can be applied as a nonintrusive concentration-measurement technique in a rotating engineering test rig.

Locality of Area Coverage on Digital Acoustic Communication in Air using Differential Phase Shift Keying

NASA Astrophysics Data System (ADS)

Mizutani, Keiichi; Ebihara, Tadashi; Wakatsuki, Naoto; Mizutani, Koichi

2009-07-01

We experimentally evaluate the locality of digital acoustic communication in air. Digital acoustic communication in air is suitable for a small cell system, because acoustic waves have a short propagation distance in air. In this study, optimal cell size is experimentally evaluated. Each base station (BS) transmits different commands. In our experiment, differential phase shift keying (DPSK), especially binary DPSK (DBPSK), is adopted as a modulation and demodulation scheme. The evaluated system consists of a personal computer (PC), a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), a loud speaker (SP), a microphone (MIC), and transceiver software. All experiments are performed in an anechoic room. The cell size of the transmitter can be limited under low signal-to-noise ratio (SNR) condition. If another transmitter works, cell size is limited by the effect of the interference from that transmitter. The cell size-to-distance ratio of transmitter A to transmitter B is 37.5%, if cell edge bit-error-rate (BER) is taken as 10-3.

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

Accumulation-mode aerosol number concentrations in the Arctic during the ARCTAS aircraft campaign: Long-range transport of polluted and clean air from the Asian continent

NASA Astrophysics Data System (ADS)

Matsui, H.; Kondo, Y.; Moteki, N.; Takegawa, N.; Sahu, L. K.; Koike, M.; Zhao, Y.; Fuelberg, H. E.; Sessions, W. R.; Diskin, G.; Anderson, B. E.; Blake, D. R.; Wisthaler, A.; Cubison, M. J.; Jimenez, J. L.

2011-10-01

We evaluate the impact of transport from midlatitudes on aerosol number concentrations in the accumulation mode (light-scattering particles (LSP) with diameters >180 nm) in the Arctic during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) campaign. We focus on transport from the Asian continent. We find marked contrasts in the number concentration (NLSP), transport efficiency (TEN_LSP, the fraction transported from sources to the Arctic), size distribution, and the chemical composition of aerosols between air parcels from anthropogenic sources in East Asia (Asian AN) and biomass burning sources in Russia and Kazakhstan (Russian BB). Asian AN air had lower NLSP and TEN_LSP (25 cm-3 and 18% in spring and 6.2 cm-3 and 3.0% in summer) than Russian BB air (280 cm-3 and 97% in spring and 36 cm-3 and 7.6% in summer) due to more efficient wet scavenging during transport from East Asia. Russian BB in this spring is the most important source of accumulation-mode aerosols over the Arctic, and BB emissions are found to be the primary source of aerosols within all the data in spring during ARCTAS. On the other hand, the contribution of Asian AN transport had a negligible effect on the accumulation-mode aerosol number concentration in the Arctic during ARCTAS. Compared with background air, NLSP was 2.3-4.7 times greater for Russian BB air but 2.4-2.6 times less for Asian AN air in both spring and summer. This result shows that the transport of Asian AN air decreases aerosol number concentrations in the Arctic, despite the large emissions of aerosols in East Asia. The very low aerosol number concentrations in Asian AN air were caused by wet removal during vertical transport in association with warm conveyor belts (WCBs). Therefore, this cleansing effect will be prominent for air transported via WCBs from other midlatitude regions and seasons. The inflow of clean midlatitude air can potentially have an important impact on

Particle Concentrations and Effectiveness of Free-Standing Air Filters in Bedrooms of Children with Asthma in Detroit, Michigan.

PubMed

Du, Liuliu; Batterman, Stuart; Parker, Edith; Godwin, Christopher; Chin, Jo-Yu; O'Toole, Ashley; Robins, Thomas; Brakefield-Caldwell, Wilma; Lewis, Toby

2011-10-01

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 (CO(2)), 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 CO(2) 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.

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...

Dynamic adaptive chemistry with operator splitting schemes for reactive flow simulations

NASA Astrophysics Data System (ADS)

Ren, Zhuyin; Xu, Chao; Lu, Tianfeng; Singer, Michael A.

2014-04-01

A numerical technique that uses dynamic adaptive chemistry (DAC) with operator splitting schemes to solve the equations governing reactive flows is developed and demonstrated. Strang-based splitting schemes are used to separate the governing equations into transport fractional substeps and chemical reaction fractional substeps. The DAC method expedites the numerical integration of reaction fractional substeps by using locally valid skeletal mechanisms that are obtained using the directed relation graph (DRG) reduction method to eliminate unimportant species and reactions from the full mechanism. Second-order temporal accuracy of the Strang-based splitting schemes with DAC is demonstrated on one-dimensional, unsteady, freely-propagating, premixed methane/air laminar flames with detailed chemical kinetics and realistic transport. The use of DAC dramatically reduces the CPU time required to perform the simulation, and there is minimal impact on solution accuracy. It is shown that with DAC the starting species and resulting skeletal mechanisms strongly depend on the local composition in the flames. In addition, the number of retained species may be significant only near the flame front region where chemical reactions are significant. For the one-dimensional methane/air flame considered, speed-up factors of three and five are achieved over the entire simulation for GRI-Mech 3.0 and USC-Mech II, respectively. Greater speed-up factors are expected for larger chemical kinetics mechanisms.

Short-term 222Rn activity concentration changes in underground spaces with limited air exchange with the atmosphere

NASA Astrophysics Data System (ADS)

Fijałkowska-Lichwa, L.; Przylibski, T. A.

2011-04-01

The authors investigated short-time changes in 222Rn activity concentration occurring yearly in two underground tourist facilities with limited air exchange with the atmosphere. One of them is Niedźwiedzia (Bear) Cave in Kletno, Poland - a natural space equipped with locks ensuring isolation from the atmosphere. The other site is Fluorite Adit in Kletno, a section of a disused uranium mine. This adit is equipped with a mechanical ventilation system, operated periodically outside the opening times (at night). Both sites are situated within the same metamorphic rock complex, at similar altitudes, about 2 km apart. The measurements conducted revealed spring and autumn occurrence of convective air movements. In Bear Cave, this process causes a reduction in 222Rn activity concentration in the daytime, i.e. when tourists, guides and other staff are present in the cave. From the point of view of radiation protection, this is the best situation. For the rest of the year, daily concentrations of 222Rn activity in the cave are very stable. In Fluorite Adit, on the other hand, significant variations in daily 222Rn activity concentrations are recorded almost all year round. These changes are determined by the periods of activity and inactivity of mechanical ventilation. Unfortunately this is inactive in the daytime, which results in the highest values of 222Rn activity concentration at the times when tourists and staff are present in the adit. Slightly lower concentrations of radon in Fluorite Adit are recorded in the winter season, when convective air movements carry a substantial amount of radon out into the atmosphere. The incorrect usage of mechanical ventilation in Fluorite Adit results in the most unfavourable conditions in terms of radiation protection. The staff working in that facility are exposed practically throughout the year to the highest 222Rn activity concentrations, both at work (in the adit) and at home (outside their working hours). Therefore, not very well

Reduced Ultrafine Particle Concentration in Urban Air: Changes in Nucleation and Anthropogenic Emissions.

PubMed

Saha, Provat K; Robinson, Ellis S; Shah, Rishabh U; Zimmerman, Naomi; Apte, Joshua S; Robinson, Allen L; Presto, Albert A

2018-06-19

Nucleation is an important source of ambient ultrafine particles (UFP). We present observational evidence of the changes in the frequency and intensity of nucleation events in urban air by analyzing long-term particle size distribution measurements at an urban background site in Pittsburgh, Pennsylvania during 2001-2002 and 2016-2017. We find that both frequency and intensity of nucleation events have been reduced by 40-50% over the past 15 years, resulting in a 70% reduction in UFP concentrations from nucleation. On average, the particle growth rates are 30% slower than 15 years ago. We attribute these changes to dramatic reductions in SO 2 (more than 90%) and other pollutant concentrations. Overall, UFP concentrations in Pittsburgh have been reduced by ∼48% in the past 15 years, with a ∼70% reduction in nucleation, ∼27% in weekday local sources (e.g., weekday traffic), and 49% in the regional background. Our results highlight that a reduction in anthropogenic emissions can considerably reduce nucleation events and UFP concentrations in a polluted urban environment.

Silica Gel Coated Spherical Micro resonator for Ultra-High Sensitivity Detection of Ammonia Gas Concentration in Air.

PubMed

Mallik, Arun Kumar; Farrell, Gerald; Liu, Dejun; Kavungal, Vishnu; Wu, Qiang; Semenova, Yuliya

2018-01-26

A silica gel coated microsphere resonator is proposed and experimentally demonstrated for measurements of ammonia (NH 3 ) concentration in air with ultra-high sensitivity. The optical properties of the porous silica gel layer change when it is exposed to low (parts per million (ppm)) and even ultra-low (parts per billion (ppb)) concentrations of ammonia vapor, leading to a spectral shift of the WGM resonances in the transmission spectrum of the fiber taper. The experimentally demonstrated sensitivity of the proposed sensor to ammonia is estimated as 34.46 pm/ppm in the low ammonia concentrations range from 4 ppm to 30 ppm using an optical spectrum analyser (OSA), and as 800 pm/ppm in the ultra-low range of ammonia concentrations from 2.5 ppb to 12 ppb using the frequency detuning method, resulting in the lowest detection limit (by two orders of magnitude) reported to date equal to 0.16 ppb of ammonia in air. In addition, the sensor exhibits excellent selectivity to ammonia and very fast response and recovery times measured at 1.5 and 3.6 seconds, respectively. Other attractive features of the proposed sensor are its compact nature, simplicity of fabrication.

Air Pollution and Preterm Birth in the U.S. State of Georgia (2002-2006): Associations with Concentrations of 11 Ambient Air Pollutants Estimated by Combining Community Multiscale Air Quality Model (CMAQ) Simulations with Stationary Monitor Measurements.

PubMed

Hao, Hua; Chang, Howard H; Holmes, Heather A; Mulholland, James A; Klein, Mitch; Darrow, Lyndsey A; Strickland, Matthew J

2016-06-01

Previous epidemiologic studies suggest associations between preterm birth and ambient air pollution. We investigated associations between 11 ambient air pollutants, estimated by combining Community Multiscale Air Quality model (CMAQ) simulations with measurements from stationary monitors, and risk of preterm birth (< 37 weeks of gestation) in the U.S. state of Georgia. Birth records for singleton births ≥ 27 weeks of gestation with complete covariate information and estimated dates of conception between 1 January 2002 and 28 February 2006 were obtained from the Office of Health Indicators for Planning, Georgia Department of Public Health (n = 511,658 births). Daily pollutant concentrations at 12-km resolution were estimated for 11 ambient air pollutants. We used logistic regression with county-level fixed effects to estimate associations between preterm birth and average pollutant concentrations during the first and second trimester. Discrete-time survival models were used to estimate third-trimester and total pregnancy associations. Effect modification was investigated by maternal education, race, census tract poverty level, and county-level urbanicity. Trimester-specific and total pregnancy associations (p < 0.05) were observed for several pollutants. All the traffic-related pollutants (carbon monoxide, nitrogen dioxide, PM2.5 elemental carbon) were associated with preterm birth [e.g., odds ratios for interquartile range increases in carbon monoxide during the first, second, and third trimesters and total pregnancy were 1.005 (95% CI: 1.001, 1.009), 1.007 (95% CI: 1.002, 1.011), 1.010 (95% CI: 1.006, 1.014), and 1.011 (95% CI: 1.006, 1.017)]. Associations tended to be higher for mothers with low educational attainment and African American mothers. Several ambient air pollutants were associated with preterm birth; associations were observed in all exposure windows. Hao H, Chang HH, Holmes HA, Mulholland JA, Klein M, Darrow LA, Strickland MJ. 2016. Air pollution

Short-term temperature-dependent air-surface exchange and atmospheric concentrations of polychlorinated naphthalenes and organochlorine pesticides

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

Lee, R.G.M.; Burnett, V.; Harner, T.

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 andmore » 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.« less

Thermal conditions and perceived air quality in an air-conditioned auditorium

NASA Astrophysics Data System (ADS)

Polednik, Bernard; Guz, Łukasz; Skwarczyński, Mariusz; Dudzińska, Marzenna R.

2016-07-01

The study reports measurements of indoor air temperature (T) and relative humidity (RH), perceived air quality (PAQ) and CO2, fine aerosol particle number (PN) and mass (PM1) concentrations in an air conditioned auditorium. The measurements of these air physical parameters have been carried out in the unoccupied auditorium with the air conditioning system switched off (AC off mode) and in the unoccupied and occupied auditorium with the air conditioning system switched off during the night and switched on during the day (AC on/off mode). The average indoor air thermal parameters, CO2 concentration and the PAQ value (in decipols) were elevated, while average PM1 concentration was lower in the AC on/off mode. A statistically significant (p < 0.001) positive correlation has been observed between T and PAQ values and CO2 concentrations (r = 0.66 and r = 0.59, respectively) in that AC mode. A significant negative correlation has been observed between T and PN and PM1 concentrations (r = -0.38 and r = -0.49, respectively). In the AC off mode the above relations between T and the particle concentrations were not that unequivocal. These findings may be of importance as they indicate that in certain AC operation modes the indoor air quality deteriorates along with the variation of the indoor air microclimate and room occupation. This, in turn, may adversely affect the comfort and productivity of the users of air conditioned premises.

Spatial distribution of and seasonal variations in endosulfan concentrations in soil, air, and biota around a contaminated site.

PubMed

Fang, Yanyan; Nie, Zhiqiang; Yang, Jinzhong; Die, Qingqi; Tian, Yajun; Liu, Feng; He, Jie; Wang, Jianyuan; Huang, Qifei

2018-06-12

Soil, air, tree bark, rice, wheat, invertebrates, and chicken tissues around a typical endosulfan-contaminated site were analyzed in each season in each of two years. The total endosulfan (the sum of α-, β-endosulfan and endosulfan sulfate) were significantly different in soil and air samples collected in the four seasons (P < 0.01) and the mean concentrations were 6.53 ng/g dry weight (d.w.) and 2.40 ng/m 3 , respectively, in autumn, 3.32 ng/g d.w. and 2.48 ng/m 3 , respectively, in winter, 2.10 ng/g d.w. and 0.93 ng/m 3 , respectively, in spring, and 1.03 ng/g d.w. and 0.83 ng/m 3 , respectively, in summer. The total endosulfan concentrations in tree bark, rice, wheat, and invertebrates were 23.0-278 (mean 95.5) ng/g d.w., 7.36-35.5 (mean 17.4) ng/g d.w., 34.3-158 (mean 83.1) ng/g d.w., and 401-4354 (mean 2125) ng/g lipid weight, respectively. The total endosulfan concentrations in the chicken gizzard, heart, liver, and meat samples were 552, 212, 699, and 221 ng/g lipid weight, respectively. The endosulfan concentrations in soil, air, and biota around the site were strongly influenced by endosulfan emissions from the site, and the concentrations had decreased to half the initial concentrations six months after endosulfan production stopped. The invertebrate and chicken bioconcentration and biomagnification factors indicated that endosulfan accumulated in the invertebrates and chicken tissues was slightly biomagnified by chickens. Copyright © 2018 Elsevier Inc. All rights reserved.

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.

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

PubMed

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

2010-07-01

The impact of air pollution on school children's health is currently one of the key foci of international and national agencies. Of particular concern are ultrafine particles which are emitted in large quantities, contain large concentrations of toxins and are deposited deeply in the respiratory tract. In this study, an intensive sampling campaign of indoor and outdoor airborne particulate matter was carried out in a primary school in February 2006 to investigate indoor and outdoor particle number (PN) and mass concentrations (PM(2.5)), and particle size distribution, and to evaluate the influence of outdoor air pollution on the indoor air. For outdoor PN and PM(2.5), early morning and late afternoon peaks were observed on weekdays, which are consistent with traffic rush hours, indicating the predominant effect of vehicular emissions. However, the temporal variations of outdoor PM(2.5) and PN concentrations occasionally showed extremely high peaks, mainly due to human activities such as cigarette smoking and the operation of mower near the sampling site. The indoor PM(2.5) level was mainly affected by the outdoor PM(2.5) (r = 0.68, p < 0.01), whereas the indoor PN concentration had some association with outdoor PN values (r = 0.66, p < 0.01) even though the indoor PN concentration was occasionally influenced by indoor sources, such as cooking, cleaning and floor polishing activities. Correlation analysis indicated that the outdoor PM(2.5) was inversely correlated with the indoor to outdoor PM(2.5) ratio (I/O ratio; r = -0.49, p < 0.01), while the indoor PN had a weak correlation with the I/O ratio for PN (r = 0.34, p < 0.01). The results showed that occupancy did not cause any major changes to the modal structure of particle number and size distribution, even though the I/O ratio was different for different size classes. The I/O curves had a maximum value for particles with diameters of 100-400 nm under both occupied and unoccupied scenarios, whereas no significant

Subsurface occurrence and potential source areas of chlorinated ethenes identified using concentrations and concentration ratios, Air Force Plant 4 and Naval Air Station-Joint Reserve Base Carswell Field, Fort Worth, Texas

USGS Publications Warehouse

Garcia, C. Amanda

2005-01-01

The U.S. Geological Survey, in cooperation with the U.S. Air Force Aeronautical Systems Center, Environmental Management Directorate, conducted a study during 2003-05 to characterize the subsurface occurrence and identify potential source areas of the volatile organic compounds classified as chlorinated ethenes at U.S. Air Force Plant 4 (AFP4) and adjacent Naval Air Station-Joint Reserve Base Carswell Field (NAS-JRB) at Fort Worth, Texas. The solubilized chlorinated ethenes detected in the alluvial aquifer originated as either released solvents (tetrachloroethene [PCE], trichloroethene [TCE], and trans-1,2-dichloroethene [trans-DCE]) or degradation products of the released solvents (TCE, cis-1,2-dichloroethene [cis-DCE], and trans-DCE). The combined influences of topographic- and bedrock-surface configurations result in a water table that generally slopes away from a ground-water divide approximately coincident with bedrock highs and the 1-mile-long aircraft assembly building at AFP4. Highest TCE concentrations (10,000 to 920,000 micrograms per liter) occur near Building 181, west of Building 12, and at landfill 3. Highest PCE concentrations (500 to 920 micrograms per liter) occur near Buildings 4 and 5. Highest cis-DCE concentrations (5,000 to 710,000 micrograms per liter) occur at landfill 3. Highest trans-DCE concentrations (1,000 to 1,700 micrograms per liter) occur just south of Building 181 and at landfill 3. Ratios of parent-compound to daughter-product concentrations that increase in relatively short distances (tens to 100s of feet) along downgradient ground-water flow paths can indicate a contributing source in the vicinity of the increase. Largest increases in ratio of PCE to TCE concentrations are three orders of magnitude from 0.01 to 2.7 and 7.1 between nearby wells in the northeastern part of NAS-JRB. In the northern part of NAS-JRB, the largest increases in TCE to total DCE concentration ratios relative to ratios at upgradient wells are from 17 to

Modeled and monitored variation in space and time of PCB-153 concentrations in air, sediment, soil and aquatic biota on a European scale.

PubMed

Hauck, Mara; Huijbregts, Mark A J; Hollander, Anne; Hendriks, A Jan; van de Meent, Dik

2010-08-15

We evaluated various modeling options for estimating concentrations of PCB-153 in the environment and in biota across Europe, using a nested multimedia fate model coupled with a bioaccumulation model. The most detailed model set up estimates concentrations in air, soil, fresh water sediment and fresh water biota with spatially explicit environmental characteristics and spatially explicit emissions to air and water in the period 1930-2005. Model performance was evaluated with the root mean square error (RMSE(log)), based on the difference between estimated and measured concentrations. The RMSE(log) was 5.4 for air, 5.6-6.3 for sediment and biota, and 5.5 for soil in the most detailed model scenario. Generally, model estimations tended to underestimate observed values for all compartments, except air. The decline in observed concentrations was also slightly underestimated by the model for the period where measurements were available (1989-2002). Applying a generic model setup with averaged emissions and averaged environmental characteristics, the RMSE(log) increased to 21 for air and 49 for sediment. For soil the RMSE(log) decreased to 3.5. We found that including spatial variation in emissions was most relevant for all compartments, except soil, while including spatial variation in environmental characteristics was less influential. For improving predictions of concentrations in sediment and aquatic biota, including emissions to water was found to be relevant as well. Copyright 2009 Elsevier B.V. All rights reserved.

A pilot study using scripted ventilation conditions to identify key factors affecting indoor pollutant concentration and air exchange rate in a residence.

PubMed

Johnson, Ted; Myers, Jeffrey; Kelly, Thomas; Wisbith, Anthony; Ollison, Will

2004-01-01

A pilot study was conducted using an occupied, single-family test house in Columbus, OH, to determine whether a script-based protocol could be used to obtain data useful in identifying the key factors affecting air-exchange rate (AER) and the relationship between indoor and outdoor concentrations of selected traffic-related air pollutants. The test script called for hourly changes to elements of the test house considered likely to influence air flow and AER, including the position (open or closed) of each window and door and the operation (on/off) of the furnace, air conditioner, and ceiling fans. The script was implemented over a 3-day period (January 30-February 1, 2002) during which technicians collected hourly-average data for AER, indoor, and outdoor air concentrations for six pollutants (benzene, formaldehyde (HCHO), polycyclic aromatic hydrocarbons (PAH), carbon monoxide (CO), nitric oxide (NO), and nitrogen oxides (NO(x))), and selected meteorological variables. Consistent with expectations, AER tended to increase with the number of open exterior windows and doors. The 39 AER values measured during the study when all exterior doors and windows were closed varied from 0.36 to 2.29 h(-1) with a geometric mean (GM) of 0.77 h(-1) and a geometric standard deviation (GSD) of 1.435. The 27 AER values measured when at least one exterior door or window was opened varied from 0.50 to 15.8 h(-1) with a GM of 1.98 h(-1) and a GSD of 1.902. AER was also affected by temperature and wind speed, most noticeably when exterior windows and doors were closed. Results of a series of stepwise linear regression analyses suggest that (1) outdoor pollutant concentration and (2) indoor pollutant concentration during the preceding hour were the "variables of choice" for predicting indoor pollutant concentration in the test house under the conditions of this study. Depending on the pollutant and ventilation conditions, one or more of the following variables produced a small, but

Factors Affecting the 7Be Concentration in Surface Air Over a Long Period of Monitoring in São Paulo, Brazil

NASA Astrophysics Data System (ADS)

Damatto, S.; Maduar, M.; Pecequilo, B.; Nogueira, P.; Nisti, M.

2014-12-01

Beryllium-7 (T1/2 = 53.3 days), a cosmogenic radionuclide produced continuosly in the upper atmosphere by cosmic ray spallation reactions with oxygen and nitrogen can be found in different compartments of the environment and its concentration is influenced by several factors, such as, temperature, precipitation, air velocity, air masses, altitude and as well as latitude. It is quickly attached to aerosols after its formation, becoming a useful tool to study the dynamics of aerosol particles in the atmosphere. Long-term measurements of the spatial and temporal variation of 7Be allows assessment of the influence of these factors. Data of 7Be concentrations in rainfall, air surface, soil and sediments are very well reported in Northern Hemisphere; however these same results are limited in Southern Hemisphere. During a period of 13 years, from October 2001 to October 2014, 7Be concentration was measured every 15 days in surface air at Instituto de Pesquisas Energéticas e Nucleares (IPEN), in the city of São Paulo, São Paulo, Brazil. IPEN campus is located approximately 10 km west from downtown of the city of São Paulo, which is situated on a plateau in Southeastern Brazil, at latitude 23°33'58.27"S and longitude 46°44'14.82"W and an average altitude of 760m above sea level. The climate in the area is temperate tropical with dry period in winter and rainy in summer. The concentrations of 7Be in air filters were measured by non-destructive g-ray spectrometry using a coaxial Be-layer HPGe detector with 15% relative efficiency and live counting time ranged from 100,000s to 250,000 s. The results obtained were correlated to seasons, rainfall, temperature and sunspot number. The concentrations displayed clearly seasonal variations with higher values in spring and summer time and with the amount of precipitation.

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

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...

Contribution of solid fuel, gas combustion, or tobacco smoke to indoor air pollutant concentrations in Irish and Scottish homes.

PubMed

Semple, S; Garden, C; Coggins, M; Galea, K S; Whelan, P; Cowie, H; Sánchez-Jiménez, A; Thorne, P S; Hurley, J F; Ayres, J G

2012-06-01

  There are limited data describing pollutant levels inside homes that burn solid fuel within developed country settings with most studies describing test conditions or the effect of interventions. This study recruited homes in Ireland and Scotland where open combustion processes take place. Open combustion was classified as coal, peat, or wood fuel burning, use of a gas cooker or stove, or where there is at least one resident smoker. Twenty-four-hour data on airborne concentrations of particulate matter<2.5 μm in size (PM2.5), carbon monoxide (CO), endotoxin in inhalable dust and carbon dioxide (CO2), together with 2-3 week averaged concentrations of nitrogen dioxide (NO2) were collected in 100 houses during the winter and spring of 2009-2010. The geometric mean of the 24-h time-weighted-average (TWA) PM2.5 concentration was highest in homes with resident smokers (99 μg/m3--much higher than the WHO 24-h guidance value of 25 μg/m3). Lower geometric mean 24-h TWA levels were found in homes that burned coal (7 μg/m3) or wood (6 μg/m3) and in homes with gas cookers (7 μg/m3). In peat-burning homes, the average 24-h PM2.5 level recorded was 11 μg/m3. Airborne endotoxin, CO, CO2, and NO2 concentrations were generally within indoor air quality guidance levels. Little is known about indoor air quality (IAQ) in homes that burn solid or fossil-derived fuels in economically developed countries. Recent legislative changes have moved to improve IAQ at work and in enclosed public places, but there remains a real need to begin the process of quantifying the health burden that arises from indoor air pollution within domestic environments. This study demonstrates that homes in Scotland and Ireland that burn solid fuels or gas for heating and cooking have concentrations of air pollutants generally within guideline levels. Homes where combustion of cigarettes takes place have much poorer air quality. © 2011 John Wiley & Sons A/S.

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

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

International system of units traceable results of Hg mass concentration at saturation in air from a newly developed measurement procedure.

PubMed

Quétel, Christophe R; Zampella, Mariavittoria; Brown, Richard J C; Ent, Hugo; Horvat, Milena; Paredes, Eduardo; Tunc, Murat

2014-08-05

Data most commonly used at present to calibrate measurements of mercury vapor concentrations in air come from a relationship known as the "Dumarey equation". It uses a fitting relationship to experimental results obtained nearly 30 years ago. The way these results relate to the international system of units (SI) is not known. This has caused difficulties for the specification and enforcement of limit values for mercury concentrations in air and in emissions to air as part of national or international legislation. Furthermore, there is a significant discrepancy (around 7% at room temperature) between the Dumarey data and data calculated from results of mercury vapor pressure measurements in the presence of only liquid mercury. As an attempt to solve some of these problems, a new measurement procedure is described for SI traceable results of gaseous Hg concentrations at saturation in milliliter samples of air. The aim was to propose a scheme as immune as possible to analytical biases. It was based on isotope dilution (ID) in the liquid phase with the (202)Hg enriched certified reference material ERM-AE640 and measurements of the mercury isotope ratios in ID blends, subsequent to a cold vapor generation step, by inductively coupled plasma mass spectrometry. The process developed involved a combination of interconnected valves and syringes operated by computer controlled pumps and ensured continuity under closed circuit conditions from the air sampling stage onward. Quantitative trapping of the gaseous mercury in the liquid phase was achieved with 11.5 μM KMnO4 in 2% HNO3. Mass concentrations at saturation found from five measurements under room temperature conditions were significantly higher (5.8% on average) than data calculated from the Dumarey equation, but in agreement (-1.2% lower on average) with data based on mercury vapor pressure measurement results. Relative expanded combined uncertainties were estimated following a model based approach. They ranged from 2

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

Prediction of air pollutant concentration based on sparse response back-propagation training feedforward neural networks.

PubMed

Ding, Weifu; Zhang, Jiangshe; Leung, Yee

2016-10-01

In this paper, we predict air pollutant concentration using a feedforward artificial neural network inspired by the mechanism of the human brain as a useful alternative to traditional statistical modeling techniques. The neural network is trained based on sparse response back-propagation in which only a small number of neurons respond to the specified stimulus simultaneously and provide a high convergence rate for the trained network, in addition to low energy consumption and greater generalization. Our method is evaluated on Hong Kong air monitoring station data and corresponding meteorological variables for which five air quality parameters were gathered at four monitoring stations in Hong Kong over 4 years (2012-2015). Our results show that our training method has more advantages in terms of the precision of the prediction, effectiveness, and generalization of traditional linear regression algorithms when compared with a feedforward artificial neural network trained using traditional back-propagation.

Air Pollution and Preterm Birth in the U.S. State of Georgia (2002–2006): Associations with Concentrations of 11 Ambient Air Pollutants Estimated by Combining Community Multiscale Air Quality Model (CMAQ) Simulations with Stationary Monitor Measurements

PubMed Central

Hao, Hua; Chang, Howard H.; Holmes, Heather A.; Mulholland, James A.; Klein, Mitch; Darrow, Lyndsey A.; Strickland, Matthew J.

2015-01-01

Background: Previous epidemiologic studies suggest associations between preterm birth and ambient air pollution. Objective: We investigated associations between 11 ambient air pollutants, estimated by combining Community Multiscale Air Quality model (CMAQ) simulations with measurements from stationary monitors, and risk of preterm birth (< 37 weeks of gestation) in the U.S. state of Georgia. Methods: Birth records for singleton births ≥ 27 weeks of gestation with complete covariate information and estimated dates of conception between 1 January 2002 and 28 February 2006 were obtained from the Office of Health Indicators for Planning, Georgia Department of Public Health (n = 511,658 births). Daily pollutant concentrations at 12-km resolution were estimated for 11 ambient air pollutants. We used logistic regression with county-level fixed effects to estimate associations between preterm birth and average pollutant concentrations during the first and second trimester. Discrete-time survival models were used to estimate third-trimester and total pregnancy associations. Effect modification was investigated by maternal education, race, census tract poverty level, and county-level urbanicity. Results: Trimester-specific and total pregnancy associations (p < 0.05) were observed for several pollutants. All the traffic-related pollutants (carbon monoxide, nitrogen dioxide, PM2.5 elemental carbon) were associated with preterm birth [e.g., odds ratios for interquartile range increases in carbon monoxide during the first, second, and third trimesters and total pregnancy were 1.005 (95% CI: 1.001, 1.009), 1.007 (95% CI: 1.002, 1.011), 1.010 (95% CI: 1.006, 1.014), and 1.011 (95% CI: 1.006, 1.017)]. Associations tended to be higher for mothers with low educational attainment and African American mothers. Conclusion: Several ambient air pollutants were associated with preterm birth; associations were observed in all exposure windows. Citation: Hao H, Chang HH, Holmes HA

Leukotriene-B4 concentrations in exhaled breath condensate and lung function after thirty minutes of breathing technically dried compressed air.

PubMed

Neubauer, Birger; Struck, Niclas; Mutzbauer, Till S; Schotte, Ulrich; Langfeldt, Norbert; Tetzlaff, Kay

2002-01-01

In previous studies it had been shown that leukotriene-B4 [LTB4] concentrations in the exhaled breath mirror the inflammatory activity of the airways if the respiratory tract has been exposed to occupational hazards. In diving the respiratory tract is exposed to cold and dry air and the nasopharynx, as the site of breathing-gas warming and humidification, is bypassed. The aim of the present study was to obtain LTB4-concentrations in the exhaled breath and spirometric data of 17 healthy subjects before and after thirty minutes of technically dried air breathing at normobar ambient pressure. The exhaled breath was collected non-invasively, via a permanently cooled expiration tube. The condensate was measured by a standard enzyme immunoassay for LTB4. Lung function values (FVC, FEV1, MEF 25, MEF 50) were simultaneously obtained by spirometry. The measured pre- and post-exposure LTB4- concentrations as well as the lung function values were in the normal range. The present data gave no evidence for any inflammatory activity in the subjects' airways after thirty minutes breathing technically dried air.

Personal carbon monoxide exposures of preschool children in Helsinki, Finland—comparison to ambient air concentrations

NASA Astrophysics Data System (ADS)

Alm, S.; Mukala, K.; Tiittanen, P.; Jantunen, M. J.

The associations of personal carbon monoxide (CO) exposures with ambient air CO concentrations measured at fixed monitoring sites, were studied among 194 children aged 3-6 yr in four downtown and four suburban day-care centers in Helsinki, Finland. Each child carried a personal CO exposure monitor between 1 and 4 times for a time period of between 20 and 24 h. CO concentrations at two fixed monitoring sites were measured simultaneously. The CO concentrations measured at the fixed monitoring sites were usually lower (mean maximum 8-h concentration: 0.9 and 2.6 mg m -3) than the personal CO exposure concentrations (mean maximum 8-h concentration: 3.3 mg m -3). The fixed site CO concentrations were poor predictors of the personal CO exposure concentrations. However, the correlations between the personal CO exposure and the fixed monitoring site CO concentrations increased (-0.03--0.12 to 0.13-0.16) with increasing averaging times from 1 to 8 h. Also, the fixed monitoring site CO concentrations explained the mean daily or weekly personal CO exposures of a group of simultaneously measured children better than individual exposure CO concentrations. This study suggests that the short-term CO personal exposure of children cannot be meaningfully assessed using fixed monitoring sites.

Concentrations and co-occurrence correlations of 88 volatile organic compounds (VOCs) in the ambient air of 13 semi-rural to urban locations in the United States

USGS Publications Warehouse

Pankow, J.F.; Luo, W.; Bender, D.A.; Isabelle, L.M.; Hollingsworth, J.S.; Chen, C.; Asher, W.E.; Zogorski, J.S.

2003-01-01

The ambient air concentrations of 88 volatile organic compounds were determined in samples taken at 13 semi-rural to urban locations in Maine, Massachusetts, New Jersey, Pennsylvania, Ohio, Illinois, Louisiana, and California. The sampling periods ranged from 7 to 29 months, yielding a large data set with a total of 23,191 individual air concentration values, some of which were designated "ND" (not detected). For each compound at each sampling site, the air concentrations (ca, ppbV) are reported in terms of means, medians, and means of the detected values. The analytical method utilized adsorption/thermal desorption with air-sampling cartridges. The analytes included numerous halogenated alkanes, halogenated alkenes, ethers, alcohols, nitriles, esters, ketones, aromatics, a disulfide, and a furan. At some sites, the air concentrations of the gasoline-related aromatic compounds and the gasoline additive methyl tert-butyl ether were seasonally dependent, with concentrations that maximized in the winter. For each site studied here, the concentrations of some compounds were highly correlated one with another (e.g., the BTEX group (benzene, toluene, ethylbenzene, and the xylenes). Other aromatic compounds were also all generally correlated with one another, while the concentrations of other compound pairs were not correlated (e.g., benzene was not correlated with CFC-12). The concentrations found for the BTEX group were generally lower than the values that have been previously reported for urbanized and industrialized areas of other nations. ?? 2003 Elsevier Ltd. All rights reserved.

Ambient air concentrations of PCDDs, PCDFs, coplanar PCBs, and PAHs at the Mississippi Sandhill Crane National Wildlife Refuge, Jackson County, Mississippi

USGS Publications Warehouse

White, D.H.; Hardy, J.W.

1994-01-01

Our objective was to determine the levels of selected airborne contaminants in ambient air at the Mississippi Sandhill Crane National Wildlife Refuge, Mississippi, that might be affecting the health of endangered cranes living there. Two high-volume air samplers were operated at separate locations on the Refuge during May?September 1991. The sampling media were micro-quartz filters in combination with polyurethane foam plugs. Composite bimonthly samples from each station were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), coplanar polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). Overall, residue concentrations were low. The toxic PCDD isomer 2,3,7,8-tetra-CDD was not detected, nor was penta-CDD. There was no difference (P>0.05) in residue concentrations between stations or over time and meteorological parameters were not correlated with residue concentrations. Because contaminant levels and patterns may differ seasonally, we recommend that air samples collected during winter months also be analyzed for these same chemical groups.

Vertical profile of tritium concentration in air during a chronic atmospheric HT release.

PubMed

Noguchi, Hiroshi; Yokoyama, Sumi

2003-03-01

The vertical profiles of tritium gas and tritiated water concentrations in air, which would have an influence on the assessment of tritium doses as well as on the environmental monitoring of tritium, were measured in a chronic tritium gas release experiment performed in Canada in 1994. While both of the profiles were rather uniform during the day because of atmospheric mixing, large gradients of the profiles were observed at night. The gradient coefficients of the profiles were derived from the measurements. Correlations were analyzed between the gradient coefficients and meteorological conditions: solar radiation, wind speed, and turbulent diffusivity. It was found that the solar radiation was highly correlated with the gradient coefficients of tritium gas and tritiated water profiles and that the wind speed and turbulent diffusivity showed weaker correlations with those of tritiated water profiles. A one-dimensional tritium transport model was developed to analyze the vertical diffusion of tritiated water re-emitted from the ground into the atmosphere. The model consists of processes of tritium gas deposition to soil including oxidation into tritiated water, reemission of tritiated water, dilution of tritiated water in soil by rain, and vertical diffusion of tritiated water in the atmosphere. The model accurately represents the accumulation of tritiated water in soil water and the time variations and vertical profiles of tritiated water concentrations in air.

[Microbial air purity in hospitals. Operating theatres with air conditioning system].

PubMed

Krogulski, Adam; Szczotko, Maciej

2010-01-01

The aim of this study was to show the influence of air conditioning control for microbial contamination of air inside the operating theatres equipped with correctly working air-conditioning system. This work was based on the results of bacteria and fungi concentration in hospital air obtained since 2001. Assays of microbial air purity conducted on atmospheric air in parallel with indoor air demonstrated that air filters applied in air-conditioning systems worked correctly in every case. To show the problem of fluctuation of bacteria concentration more precisely, every sequences of single results from successive measure series were examined independently.

Effect of Se concentration on photonic bandgap of 1-D As-S-Se/air multilayers

NASA Astrophysics Data System (ADS)

Singh, Rajpal; Suthar, B.; Bhargava, A.

2018-05-01

The photonic band structure of 1-D chalcogenide photonic crystal consisting of As-S-Se/air multilayered structure is studied. The photonic band structure is calculated using plane wave expansion method. The effect of Se constration on the photonic bandgap is studied. It is found that the photonic bandgap increases with Se-concentration and shows the red shift.

2,4,6-Trinitrotoluene (TNT) air concentrations, hemoglobin changes, and anemia cases in respirator protected TNT munitions demilitarization workers.

PubMed

Bradley, Melville D

2011-03-01

2,4,6-Trinitrotoluene (TNT) is an explosive used in munitions production that is known to cause both aplastic and hemolytic anemia in exposed workers. Anemia in a TNT worker is considered a sentinel health event (occupational) (SHE(O)) in the United States (US). Deaths have been reported secondary to aplastic anemia. Studies have shown that TNT systemic absorption is significant by both the respiratory and dermal routes. No studies encountered looked at hemoglobin change or anemia cases in respiratory protected workers. It is hypothesized that respiratory protection is insufficient to protect TNT workers from the risk of anemia development and hemoglobin concentration drop. A records review of eight groups of respiratory protected TNT workers' pre-exposure hemoglobin levels were compared with their during-exposure hemoglobin levels for statistically significant (alpha level 0.05) hemoglobin level changes, and anemia cases were recorded. A curve estimation analysis was performed between mean TNT air concentrations and mean hemoglobin change values. Statistically significant hemoglobin level drops and anemia cases were apparent at TNT air concentrations about the REL and PEL in respiratory protected workers. There were no anemia cases or statistically significant hemoglobin level drops at concentrations about the TLV, however. A statistically significant inverse non-linear regression model was found to be the best fit for regressing hemoglobin change on TNT air concentration. Respiratory protection may be inadequate to prevent workers who are at risk for TNT skin absorption from developing anemia. This study contributes evidence that the TLV should be considered for adoption as the new PEL.

Control of aerosol contaminants in indoor air: combining the particle concentration reduction with microbial inactivation.

PubMed

Grinshpun, Sergey A; Adhikari, Atin; Honda, Takeshi; Kim, Ki Youn; Toivola, Mika; Rao, K S Ramchander; Reponen, Tiina

2007-01-15

An indoor air purification technique, which combines unipolar ion emission and photocatalytic oxidation (promoted by a specially designed RCI cell), was investigated in two test chambers, 2.75 m3 and 24.3 m3, using nonbiological and biological challenge aerosols. The reduction in particle concentration was measured size selectively in real-time, and the Air Cleaning Factor and the Clean Air Delivery Rate (CADR) were determined. While testing with virions and bacteria, bioaerosol samples were collected and analyzed, and the microorganism survival rate was determined as a function of exposure time. We observed that the aerosol concentration decreased approximately 10 to approximately 100 times more rapidly when the purifier operated as compared to the natural decay. The data suggest that the tested portable unit operating in approximately 25 m3 non-ventilated room is capable to provide CADR-values more than twice as great than the conventional closed-loop HVAC system with a rating 8 filter. The particle removal occurred due to unipolar ion emission, while the inactivation of viable airborne microorganisms was associated with photocatalytic oxidation. Approximately 90% of initially viable MS2 viruses were inactivated resulting from 10 to 60 min exposure to the photocatalytic oxidation. Approximately 75% of viable B. subtilis spores were inactivated in 10 min, and about 90% or greater after 30 min. The biological and chemical mechanisms that led to the inactivation of stress-resistant airborne viruses and bacterial spores were reviewed.

Evaluation of Ultra-Violet Photocatalytic Oxidation (UVPCO) forIndoor Air Applications: Conversion of Volatile Organic Compounds at LowPart-per-Billion Concentrations

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

Hodgson, Alfred T.; Sullivan, Douglas P.; Fisk, William J.

2005-09-30

Efficient removal of indoor generated airborne particles and volatile organic compounds (VOCs) in office buildings and other large buildings may allow for a reduction in outdoor air supply rates with concomitant energy savings while still maintaining acceptable indoor air quality in these buildings. Ultra-Violet Photocatalytic Oxidation (UVPCO) air cleaners have the potential to achieve the necessary reductions in indoor VOC concentrations at relatively low cost. In this study, laboratory experiments were conducted with a scaled, prototype UVPCO device designed for use in a duct system. The experimental UVPCO contained two 30 by 30-cm honeycomb monoliths coated with titanium dioxide andmore » 3% by weight tungsten oxide. The monoliths were irradiated with 12 UVC lamps arranged in four banks. The UVPCO was challenged with four mixtures of VOCs typical of mixtures encountered in indoor air. A synthetic office mixture contained 27 VOCs commonly measured in office buildings. A cleaning product mixture contained three cleaning products with high market shares. A building product mixture was created by combining sources including painted wallboard, composite wood products, carpet systems, and vinyl flooring. A fourth mixture contained formaldehyde and acetaldehyde. Steady-state concentrations were produced in a classroom laboratory or a 20-m{sup 3} environmental chamber. Air was drawn through the UVPCO, and single pass conversion efficiencies were measured from replicate air samples collected upstream and downstream of the reactor section. Concentrations of the mixtures were manipulated, with concentrations of individual VOCs mostly maintained below 10 ppb. Device flow rates were varied between 165 and 580 m{sup 3}/h. Production of formaldehyde, acetaldehyde, acetone, formic acid, and acetic acid as reaction products was investigated. Conversion efficiency data were generated for 48 individual VOCs or groups of closely related compounds. Alcohols and glycol ethers were

Validation of minicams for measuring concentrations of chemical agent in environmental air

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

Menton, R.G.; Hayes, T.L.; Chou, Y.L.

1993-05-13

Environmental monitoring for chemical agents is necessary to ensure that notification and appropriate action will be taken in the, event that there is a release exceeding control limits of such agents into the workplace outside of engineering controls. Prior to implementing new analytical procedures for environmental monitoring, precision and accuracy (PA) tests are conducted to ensure that an agent monitoring system performs according to specified accuracy, precision, and sensitivity requirements. This testing not only establishes the accuracy and precision of the method, but also determines what factors can affect the method's performance. Performance measures that are particularly important in agentmore » monitoring include the Detection Limit (DL), Decision Limit (DC), Found Action Level (FAL), and the Target Action Level (TAL). PA experiments were performed at Battelle's Medical Research and Evaluation Facility (MREF) to validate the use of the miniature chemical agent monitoring system (MINICAMs) for measuring environmental air concentrations of sulfur mustard (HD). This presentation discusses the experimental and statistical approaches for characterizing the performance of MINICAMS for measuring HD in air.« less

MODELING INDOOR CONCENTRATIONS AND EXPOSURE

EPA Science Inventory

The paper discusses the use of an indoor air quality model, EXPOSURE, to predict pollutant concentrations and exposures. The effects of indoor air pollutants depend on the concentrations of the pollutants and the exposure of individuals to the pollutants. The air pollutant concen...

Ambient air concentrations exceeded health-based standards for fine particulate matter and benzene during the Deepwater Horizon oil spill.

PubMed

Nance, Earthea; King, Denae; Wright, Beverly; Bullard, Robert D

2016-02-01

The Deepwater Horizon oil spill is considered one of the largest marine oil spills in the history of the United States. Air emissions associated with the oil spill caused concern among residents of Southeast Louisiana. The purpose of this study was to assess ambient concentrations of benzene (n=3,887) and fine particulate matter (n=102,682) during the oil spill and to evaluate potential exposure disparities in the region. Benzene and fine particulate matter (PM2.5) concentrations in the targeted parishes were generally higher following the oil spill, as expected. Benzene concentrations reached 2 to 19 times higher than background, and daily exceedances of PM2.5 were 10 to 45 times higher than background. Both benzene and PM2.5 concentrations were considered high enough to exceed public health criteria, with measurable exposure disparities in the coastal areas closer to the spill and clean-up activities. These findings raise questions about public disclosure of environmental health risks associated with the oil spill. The findings also provide a science-based rationale for establishing health-based action levels in future disasters. Benzene and particulate matter monitoring during the Deepwater Horizon oil spill revealed that ambient air quality was a likely threat to public health and that residents in coastal Louisiana experienced significantly greater exposures than urban residents. Threshold air pollution levels established for the oil spill apparently were not used as a basis for informing the public about these potential health impacts. Also, despite carrying out the most comprehensive air monitoring ever conducted in the region, none of the agencies involved provided integrated analysis of the data or conclusive statements about public health risk. Better information about real-time risk is needed in future environmental disasters.

Secondhand smoke exposure within semi-open air cafes and tobacco specific 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) concentrations among nonsmoking employees.

PubMed

Vardavas, Constantine I; Karabela, Maria; Agaku, Israel T; Matsunaga, Yuko; Myridakis, Antonis; Kouvarakis, Antonis; Stephanou, Euripides G; Lymperi, Maria; Behrakis, Panagiotis K

2014-10-01

Secondhand smoke (SHS) is a defined occupational hazard. The association though between SHS exposure in semi-open air venues and tobacco specific carcinogen uptake is an area of debate. A cross sectional survey of 49 semi-open air cafes in Athens, Greece was performed during the summer of 2008, prior to the adoption of the national smoke free legislation. All venues had at least 1 entire wall open to allow for free air exchange. Indoor concentrations of particulate matter smaller than 2.5 microns (PM2.5) attributable to SHS were assessed during a work shift, while 1 non-smoking employee responsible for indoor and outdoor table service from each venue provided a post work shift urine sample for analysis of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL). Post work shift NNAL concentrations were correlated with work shift PM2.5 concentrations attributable to SHS (r = 0.376, p = 0.0076). Urinary NNAL concentrations among employees increased by 9.5%, per 10 μg/m(3) increase in PM2.5 concentrations attributable to SHS after controlling for the time of day and day of week. These results indicate that the commonly proposed practice of maintaining open sliding walls as a means of free air exchange does not lead to the elimination of employee exposure to tobacco specific carcinogens attributable to workplace SHS.

Environmental concentration and atmospheric deposition of halogenated flame retardants in soil from Nepal: Source apportionment and soil-air partitioning.

PubMed

Yadav, Ishwar Chandra; Devi, Ningombam Linthoingambi; Li, Jun; Zhang, Gan

2018-02-01

While various investigations have been driven on polybrominated diphenyl ethers (PBDEs) and other flame retardants (FRs) in different framework around the world, information about contamination and fate of PBDEs and other FRs in developing countries especially in the Indian subcontinent is uncommon. Nepal being located in the Indian subcontinent, very little is known about contamination level of semi-volatile organic pollutants discharged into the environment. This motivated us to investigate the environmental fate of halogenated flame retardant (HFRs) in Nepalese condition. In this study, we investigated the concentration, fate, and sources of 9 PBDEs, 2 dechlorane plus isomers (DPs), and 6 novel brominated flame retardants (NBFRs). Moreover, air-soil exchange and soil-air partitioning were also evaluated to characterize the pattern of air-soil exchange and environmental fate. In general, the concentrations of NBFRs in soil were more prevalent than PBDEs and DPs, and accounted 95% of ∑HFRs. By and large, the concentrations of NBFRs and DPs were measured high in Kathmandu, while PBDEs level exceeded in Pokhara. Principal component analysis (PCA) study suggested contributions from commercial penta-, octa-, and deca-BDEs products and de-bromination of highly brominated PBDEs as the significant source of PBDEs. Likewise, low f anti ratio suggested DPs in soil might have originated from long-range atmospheric transport from remote areas, while high levels of decabromodiphenyl ethane (DBDPE) in soil were linked with the use of wide varieties of consumer products. The estimated fugacity fraction (ff) for individual HFR was quite lower (<0.05) than equilibrium value, suggesting that deposition and net transport from air to the soil is overwhelming. Soil-air partitioning study revealed neither octanol-air partition coefficient (K OA ) nor black carbon partition coefficient (K BC-A ) is an appropriate surrogate for soil organic matter (SOM), subsequently, absorption by

Modelling deposition and air concentration of reduced nitrogen in Poland and sensitivity to variability in annual meteorology.

PubMed

Kryza, Maciej; Dore, Anthony J; Błaś, Marek; Sobik, Mieczysław

2011-04-01

The relative contribution of reduced nitrogen to acid and eutrophic deposition in Europe has increased recently as a result of European policies which have been successful in reducing SO(2) and NO(x) emissions but have had smaller impacts on ammonia (NH(3)) emissions. In this paper the Fine Resolution Atmospheric Multi-pollutant Exchange (FRAME) model was used to calculate the spatial patterns of annual average ammonia and ammonium (NH(4)(+)) air concentrations and reduced nitrogen (NH(x)) dry and wet deposition with a 5 km × 5 km grid for years 2002-2005. The modelled air concentrations of NH(3) and dry deposition of NH(x) show similar spatial patterns for all years considered. The largest year to year changes were found for wet deposition, which vary considerably with precipitation amount. The FRAME modelled air concentrations and wet deposition are in reasonable agreement with available measurements (Pearson's correlation coefficients above 0.6 for years 2002-2005), and with spatial patterns of concentrations and deposition of NH(x) reported with the EMEP results, but show larger spatial gradients. The error statistics show that the FRAME model results are in better agreement with measurements if compared with EMEP estimates. The differences in deposition budgets calculated with FRAME and EMEP do not exceed 17% for wet and 6% for dry deposition, with FRAME estimates higher than for EMEP wet deposition for modelled period and lower or equal for dry deposition. The FRAME estimates of wet deposition budget are lower than the measurement-based values reported by the Chief Inspectorate of Environmental Protection of Poland, with the differences by approximately 3%. Up to 93% of dry and 53% of wet deposition of NH(x) in Poland originates from national sources. Over the western part of Poland and mountainous areas in the south, transboundary transport can contribute over 80% of total (dry + wet) NH(x) deposition. The spatial pattern of the relative contribution of

Blockade of the High-Affinity Interleukin-2 Receptors with Daclizumab High-Yield Process: Pharmacokinetic/Pharmacodynamic Analysis of Single- and Multiple-Dose Phase I Trials.

PubMed

Minocha, Mukul; Tran, Jonathan Q; Sheridan, James P; Othman, Ahmed A

2016-01-01

Daclizumab high-yield process (DAC HYP) is a humanized monoclonal antibody that selectively blocks the α-subunit (CD25) of the high-affinity interleukin-2 receptors, and has shown robust efficacy as a treatment for multiple sclerosis (MS). This work quantitatively characterized the relationship between DAC HYP serum concentrations and saturation of CD25 expressed on antigen-rich target T cells in blood. Serial pharmacokinetic and 968 CD25 measurements from three double-blind, randomized, placebo-controlled, phase I studies of DAC HYP (50-300 mg subcutaneous and 200-400 mg intravenous doses or placebo) in healthy volunteers (n = 95) were analyzed using nonlinear mixed-effects modeling. CD25 occupancy was determined using flow cytometry and a fluorescently-labeled DAC HYP-competing antibody. CD25 occupancy was described using a direct inhibitory sigmoidal maximum effect (E max) model (where DAC HYP fully inhibited CD25 labeling with competing antibody). Two IC50 (serum concentration corresponding to 50 % of maximal inhibition) parameters were used to describe rapid CD25 saturation at initiation of dosing and apparently slower desaturation during DAC HYP washout. Parameter estimates (95 % bootstrap confidence intervals) were: baseline CD25 labeling, 47 % (45-48); DAC HYP IC50(saturation), 0.023 µg/mL (0.005-0.073); IC50(desaturation) 0.86 µg/mL (0.74-0.98); Hill coefficient 5.6 (4.3-6.8). Based on the developed model, the 150 mg monthly subcutaneous regimen of DAC HYP in subjects with MS is predicted to saturate CD25 on target effector T cells within a few hours of dosing and maintain CD25 saturation during the entire dosing interval. Free CD25 levels return to baseline within 4-6 months of the last DAC HYP dose.

The association between daily concentrations of air pollution and visits to a psychiatric emergency unit: a case-crossover study.

PubMed

Oudin, Anna; Åström, Daniel Oudin; Asplund, Peter; Steingrimsson, Steinn; Szabo, Zoltan; Carlsen, Hanne Krage

2018-01-10

Air pollution is one of the leading causes of mortality and morbidity worldwide. Experimental studies, and a few epidemiological studies, suggest that air pollution may cause acute exacerbation of psychiatric disorders, and even increase the rate of suicide attempts, but epidemiological studies on air pollution in association with psychiatric disorders are still few. Our aim was to investigate associations between daily fluctuations in air pollution concentrations and the daily number of visits to a psychiatric emergency unit. Data from Sahlgrenska University Hospital, Gothenburg, Sweden, on the daily number of visits to the Psychiatric emergency unit were combined with daily data on monitored concentrations of respirable particulate matter(PM 10 ), ozone(O 3 ), nitrogen dioxides(NO 2 ) and temperature between 1st July 2012 and 31st December 2016. We used a case-crossover design to analyze data with conditional Poisson regression models allowing for over-dispersion. We stratified data on season. Visits increased with increasing PM 10 levels during the warmer season (April to September) in both single-pollutant and two-pollutant models. For example, an increase of 3.6% (95% Confidence Interval, CI, 0.4-7.0%) was observed with a 10 μg/m3 increase in PM 10 adjusted for NO 2 . In the three-pollutant models (adjusting for NO 2 and O 3 simultaneously) the increase was 3.3% (95% CI, -0.2-6.9). There were no clear associations between the outcome and NO 2 , O 3 , or PM 10 during the colder season (October to March). Ambient air particle concentrations were associated with the number of visits to the Psychiatric emergency unit in the warm season. The results were only borderline statistically significant in the fully adjusted (three-pollutant) models in this small study. The observation could be interpreted as indicative of air pollution as either exacerbating an underlying psychiatric disorder, or increasing mental distress, even in areas with comparatively low levels of

A Unified Spatiotemporal Modeling Approach for Predicting Concentrations of Multiple Air Pollutants in the Multi-Ethnic Study of Atherosclerosis and Air Pollution

PubMed Central

Olives, Casey; Kim, Sun-Young; Sheppard, Lianne; Sampson, Paul D.; Szpiro, Adam A.; Oron, Assaf P.; Lindström, Johan; Vedal, Sverre; Kaufman, Joel D.

2014-01-01

Background: Cohort studies of the relationship between air pollution exposure and chronic health effects require predictions of exposure over long periods of time. Objectives: We developed a unified modeling approach for predicting fine particulate matter, nitrogen dioxide, oxides of nitrogen, and black carbon (as measured by light absorption coefficient) in six U.S. metropolitan regions from 1999 through early 2012 as part of the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air). Methods: We obtained monitoring data from regulatory networks and supplemented those data with study-specific measurements collected from MESA Air community locations and participants’ homes. In each region, we applied a spatiotemporal model that included a long-term spatial mean, time trends with spatially varying coefficients, and a spatiotemporal residual. The mean structure was derived from a large set of geographic covariates that was reduced using partial least-squares regression. We estimated time trends from observed time series and used spatial smoothing methods to borrow strength between observations. Results: Prediction accuracy was high for most models, with cross-validation R2 (R2CV) > 0.80 at regulatory and fixed sites for most regions and pollutants. At home sites, overall R2CV ranged from 0.45 to 0.92, and temporally adjusted R2CV ranged from 0.23 to 0.92. Conclusions: This novel spatiotemporal modeling approach provides accurate fine-scale predictions in multiple regions for four pollutants. We have generated participant-specific predictions for MESA Air to investigate health effects of long-term air pollution exposures. These successes highlight modeling advances that can be adopted more widely in modern cohort studies. Citation: Keller JP, Olives C, Kim SY, Sheppard L, Sampson PD, Szpiro AA, Oron AP, Lindström J, Vedal S, Kaufman JD. 2015. A unified spatiotemporal modeling approach for predicting concentrations of multiple air pollutants in the Multi

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...

An Autonomous Circuit for the Measurement of Photovoltaic Devices Parameters.

DTIC Science & Technology

1986-09-01

Comparison Data, Gallium Arsenide ................ 80 A 7 A,. TABLE OF SYMBOLS A Curve Fitting Constant ADC Analog to Digital Converter AMO Air-Mass-Zero...in Radiation Fluence in the Logarithmic Region CMOS Complementary Metal-Oxide Semiconductor DAC Digital to Analog Converter DC Direct Current Dp Hole...characteristics of individual solar cells. A novel circuit is developed that uses a microprocessor controlled Digital to Analog Converter (DAC) to obtain

Mobile Air Monitoring: Measuring Change in Air Quality in the City of Hamilton, 2005-2010

ERIC Educational Resources Information Center

Adams, Matthew D.; DeLuca, Patrick F.; Corr, Denis; Kanaroglou, Pavlos S.

2012-01-01

This paper examines the change in air pollutant concentrations between 2005 and 2010 occurring in the City of Hamilton, Ontario, Canada. After analysis of stationary air pollutant concentration data, we analyze mobile air pollutant concentration data. Air pollutants included in the analysis are CO, PM[subscript 2.5], SO[subscript 2], NO,…

Temporal variability of indoor air concentrations under natural conditions in a house overlying a dilute chlorinated solvent groundwater plume.

PubMed

Holton, Chase; Luo, Hong; Dahlen, Paul; Gorder, Kyle; Dettenmaier, Erik; Johnson, Paul C

2013-01-01

Current vapor intrusion (VI) pathway assessment heavily weights concentrations from infrequent (monthly-seasonal) 24 h indoor air samples. This study collected a long-term and high-frequency data set that can be used to assess indoor air sampling strategies for answering key pathway assessment questions like: "Is VI occurring?", and "Will VI impacts exceed thresholds of concern?". Indoor air sampling was conducted for 2.5 years at 2-4 h intervals in a house overlying a dilute chlorinated solvent plume (10-50 μg/L TCE). Indoor air concentrations varied by 3 orders of magnitude (<0.01-10 ppbv TCE) with two recurring behaviors. The VI-active behavior, which was prevalent in fall, winter, and spring involved time-varying impacts intermixed with sporadic periods of inactivity; the VI-dormant behavior, which was prevalent in the summer, involved long periods of inactivity with sporadic VI impacts. These data were used to study outcomes of three simple sparse data sampling plans; the probabilities of false-negative and false-positive decisions were dependent on the ratio of the (action level/true mean of the data), the number of exceedances needed, and the sampling strategy. The analysis also suggested a significant potential for poor characterization of long-term mean concentrations with sparse sampling plans. The results point to a need for additional dense data sets and further investigation into the robustness of possible VI assessment paradigms. As this is the first data set of its kind, it is unknown if the results are representative of other VI-sites.

A study of building structural features associated with high indoor air concentrations of organochlorine termiticides.

PubMed

Pisaniello, D L; Gun, R T; Tkaczuk, M N; Hann, C; Crea, J

1993-09-01

As part of a two-year study of post-treatment residential exposure to the termiticide, aldrin, the building structural features of ten houses with crawl-space-type floors were assessed by an independent inspector. Building attributes recorded on a checklist included the age of the dwelling, room characteristics, floor details and the nature of subfloor ventilation. At the end of each inspection, the inspector, who was blinded to data on airborne aldrin concentrations, provided a rating of expected indoor air contamination. Several of the building attributes, including the age of the house, the area of exterior subfloor vents, as well as the inspector's rating, were significantly correlated with airborne aldrin values. No single building variable, however, was highly correlated with every measure of aldrin concentration over a 12-month period. The observed data are consistent with poor subfloor ventilation and a 'leaky' floor being important contributors to indoor air pollution. It is recommended that pest control companies advise householders about any obvious floor and ventilation deficiencies before soil treatment work is undertaken. Pesticide exposure (by analogy with geological radon exposure) may be reduced by sealing gaps in floors and/or by improving subfloor ventilation.

DACS II - A distributed thermal/mechanical loads data acquisition and control system

NASA Technical Reports Server (NTRS)

Zamanzadeh, Behzad; Trover, William F.; Anderson, Karl F.

1987-01-01

A distributed data acquisition and control system has been developed for the NASA Flight Loads Research Facility. The DACS II system is composed of seven computer systems and four array processors configured as a main computer system, three satellite computer systems, and 13 analog input/output systems interconnected through three independent data networks. Up to three independent heating and loading tests can be run concurrently on different test articles or the entire system can be used on a single large test such as a full scale hypersonic aircraft. Thermal tests can include up to 512 independent adaptive closed loop control channels. The control system can apply up to 20 MW of heating to a test specimen while simultaneously applying independent mechanical loads. Each thermal control loop is capable of heating a structure at rates of up to 150 F per second over a temperature range of -300 to +2500 F. Up to 64 independent mechanical load profiles can be commanded along with thermal control. Up to 1280 analog inputs monitor temperature, load, displacement and strain on the test specimens with real time data displayed on up to 15 terminals as color plots and tabular data displays. System setup and operation is accomplished with interactive menu-driver displays with extensive facilities to assist the users in all phases of system operation.

Chemodiversity of a Scots pine stand and implications for terpene air concentrations

NASA Astrophysics Data System (ADS)

Bäck, J.; Aalto, J.; Henriksson, M.; Hakola, H.; He, Q.; Boy, M.

2012-02-01

Atmospheric chemistry in background areas is strongly influenced by natural vegetation. Coniferous forests are known to produce large quantities of volatile vapors, especially terpenes. These compounds are reactive in the atmosphere, and contribute to the formation and growth of atmospheric new particles. Our aim was to analyze the variability of mono- and sesquiterpene emissions between Scots pine trees, in order to clarify the potential errors caused by using emission data obtained from only a few trees in atmospheric chemistry models. We also aimed at testing if stand history and seed origin has an influence on the chemotypic diversity. The inherited, chemotypic variability in mono- and sesquiterpene emission was studied in a seemingly homogeneous 48 yr-old stand in Southern Finland, where two areas differing in their stand regeneration history could be distinguished. Sampling was conducted in August 2009. Terpene concentrations in the air had been measured at the same site for seven years prior to branch sampling for chemotypes. Two main compounds, α-pinene and Δ3-carene formed together 40-97% of the monoterpene proportions in both the branch emissions and in the air concentrations. The data showed a bimodal distribution in emission composition, in particular in Δ3-carene emission within the studied population. 10% of the trees emitted mainly α-pinene and no Δ3-carene at all, whereas 20% of the trees where characterized as high Δ3-carene emitters (Δ3-carene forming >80% of total emitted monoterpene spectrum). An intermediate group of trees emitted equal amounts of both α-pinene and Δ3-carene. The emission pattern of trees at the area established using seeding as the artificial regeneration method differed from the naturally regenerated or planted trees, being mainly high Δ3-carene emitters. Some differences were also seen in e.g. camphene and limonene emissions between chemotypes, but sesquiterpene emissions did not differ significantly between trees

Background Indoor Air Concentrations of Volatile Organic Compounds in North American Residences (1990 – 2005): A Compilation of Statistics for Assessing Vapor Intrusion

EPA Pesticide Factsheets

This technical report presents a summary of indoor air studies that measured background concentrations of VOCs in the indoor air of thousands of North American residences and an evaluation and compilation of their reported statistical information.

The effect of long-range air mass transport pathways on PM10 and NO2 concentrations at urban and rural background sites in Ireland: Quantification using clustering techniques.

PubMed

Donnelly, Aoife A; Broderick, Brian M; Misstear, Bruce D

2015-01-01

The specific aims of this paper are to: (i) quantify the effects of various long range transport pathways nitrogen dioxide (NO2) and particulate matter with diameter less than 10μm (PM10) concentrations in Ireland and identify air mass movement corridors which may lead to incidences poor air quality for application in forecasting; (ii) compare the effects of such pathways at various sites; (iii) assess pathways associated with a period of decreased air quality in Ireland. The origin of and the regions traversed by an air mass 96h prior to reaching a receptor is modelled and k-means clustering is applied to create air-mass groups. Significant differences in air pollution levels were found between air mass cluster types at urban and rural sites. It was found that easterly or recirculated air masses lead to higher NO2 and PM10 levels with average NO2 levels varying between 124% and 239% of the seasonal mean and average PM10 levels varying between 103% and 199% of the seasonal mean at urban and rural sites. Easterly air masses are more frequent during winter months leading to higher overall concentrations. The span in relative concentrations between air mass clusters is highest at the rural site indicating that regional factors are controlling concentration levels. The methods used in this paper could be applied to assist in modelling and forecasting air quality based on long range transport pathways and forecast meteorology without the requirement for detailed emissions data over a large regional domain or the use of computationally demanding modelling techniques.

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

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

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 periodmore » 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).« less

Urinary and air phthalate concentrations and self-reported use of personal care products among minority pregnant women in New York city.

PubMed

Just, Allan C; Adibi, Jennifer J; Rundle, Andrew G; Calafat, Antonia M; Camann, David E; Hauser, Russ; Silva, Manori J; Whyatt, Robin M

2010-11-01

Diethyl phthalate (DEP) and di-n-butyl phthalate (DnBP) are used extensively in personal care products, including fragrances (DEP) and nail polish (DnBP). Between May 2003 and July 2006, we gathered questionnaire data on the use of seven product categories (deodorant, perfume, hair spray, hair gel, nail polish/polish remover, liquid soap/body wash, and lotion/mist) over 48 h during the third trimester of pregnancy from 186 inner-city women. A 48-h personal air sample was collected and analyzed for DEP and DnBP; a maternal spot urine sample was collected and analyzed for their monoester metabolites, monoethyl phthalate (MEP) and mono-n-butyl phthalate (MnBP), respectively. In all, 97% of air samples and 84% of urine samples were collected within ±2 days of the questionnaire. During the 48 h, 41% of women reported perfume use and 10% reported nail polish/polish remover use. In adjusted analyses, no association was seen between nail product use and air DnBP or urine MnBP concentrations. Women reporting perfume use had 2.3 times higher (95% CI 1.6, 3.3) urinary MEP concentrations. Personal air DEP increased by 7% for each 25% increase in a composite indicator of the six other product categories (P<0.05), but was not associated with perfume use. Air DEP was correlated with urine MEP concentrations only among non-perfume users (r=0.51, P<0.001). Results suggest that perfume use is a significant source of DEP exposure.

Urinary and air phthalate concentrations and self-reported use of personal care products among minority pregnant women in New York City

PubMed Central

Just, Allan C.; Adibi, Jennifer J.; Rundle, Andrew G.; Calafat, Antonia M.; Camann, David E.; Hauser, Russ; Silva, Manori J.; Whyatt, Robin M.

2011-01-01

Diethyl phthalate (DEP) and di-n-butyl phthalate (DnBP) are used extensively in personal care products, including fragrances (DEP) and nail polish (DnBP). Between May 2003 and July 2006, we gathered questionnaire data on use of 7 product categories (deodorant, perfume, hair spray, hair gel, nail polish/polish remover, liquid soap/body wash, lotion/mist) over 48 hours during the 3rd trimester of pregnancy from 186 inner-city women. A 48-hour personal air sample was collected and analyzed for DEP and DnBP; a maternal spot urine sample was collected and analyzed for their monoester metabolites, monoethyl phthalate (MEP) and mono-n-butyl phthalate (MnBP), respectively. Ninety-seven percent of air samples and 84% of urine samples were collected within ±2 days of the questionnaire. During the 48 hours, 41% of women reported perfume use and 10% reported nail polish/polish remover use. In adjusted analyses, no association was seen between nail product use and air DnBP or urine MnBP concentrations. Women reporting perfume use had 2.3 times higher (95% CI 1.6, 3.3) urinary MEP concentrations. Personal air DEP increased 7% for each 25% increase in a composite indicator of the 6 other product categories (p<0.05) but was not associated with perfume use. Air DEP was correlated with urine MEP concentrations only among non-perfume users (r=0.51, p<0.001). Results suggest that perfume use is a significant source of DEP exposure. PMID:20354564

The Relationship Between Temperature and Gas Concentration Fluctuation Rates at an Air-Water Interface

NASA Astrophysics Data System (ADS)

Asher, W. E.; Jessup, A. T.; Liang, H.; Zappa, C. J.

2008-12-01

The air-sea flux, F, of a sparingly soluble nonreactive gas can be expressed as F = kG(CS-CW), where kG is the gas transfer velocity, CS is the concentration of gas that would be expected in the water if the system were in Henry's Gas Law equilibrium, and CW is the gas concentration in the bulk water. An analogous relationship for the net heat flux can also be written using the heat transfer velocity, kH, and the bulk-skin temperature difference in the aqueous phase. Surface divergence theory for the air-water transfer of gas and heat predicts that kG and kH will scale as the square root of the surface divergence rate, r. However, because of the interaction between diffusivity and the scale depth of the surface divergences, the scale factor for heat is likely to be different from the scale factor for gases. Infrared imagery was used to measure the timescales of variations in temperature at a water surface and laser-induced fluorescence (LIF) was used to measure temporal fluctuations in aqueous-phase concentrations of carbon dioxide (CO2) at a water surface. The rate at which these temperature and concentration fluctuations occur is then assumed to be related to r. The divergence rates derived for temperature from the IR images can be compared to the rates for gas derived from the LIF measurements to understand how r estimated from the two measurements differ. The square root of r is compared to concurrently measured kG for helium and sulfur hexafluoride to test the assumption that r1/2 scales with kG. Additionally, we measured kH using the active controlled flux technique, and those heat transfer velocities can also be used to test for a r1/2 dependence. All measurements reported here were made in the APL-UW synthetic jet array facility.

Effects of Roof-Edge Roughness on Air Temperature and Pollutant Concentration in Urban Canyons

NASA Astrophysics Data System (ADS)

Aliabadi, Amir A.; Krayenhoff, E. Scott; Nazarian, Negin; Chew, Lup Wai; Armstrong, Peter R.; Afshari, Afshin; Norford, Leslie K.

2017-08-01

The influence of roof-edge roughness elements on airflow, heat transfer, and street-level pollutant transport inside and above a two-dimensional urban canyon is analyzed using an urban energy balance model coupled to a large-eddy simulation model. Simulations are performed for cold (early morning) and hot (mid afternoon) periods during the hottest month of the year (August) for the climate of Abu Dhabi, United Arab Emirates. The analysis suggests that early in the morning, and when the tallest roughness elements are implemented, the temperature above the street level increases on average by 0.5 K, while the pollutant concentration decreases by 2% of the street-level concentration. For the same conditions in mid afternoon, the temperature decreases conservatively by 1 K, while the pollutant concentration increases by 7% of the street-level concentration. As a passive or active architectural solution, the roof roughness element shows promise for improving thermal comfort and air quality in the canyon for specific times, but this should be further verified experimentally. The results also warrant a closer look at the effects of mid-range roughness elements in the urban morphology on atmospheric dynamics so as to improve parametrizations in mesoscale modelling.

Release of Airborne Polychlorinated Biphenyls from New Bedford Harbor Results in Elevated Concentrations in the Surrounding Air.

PubMed

Martinez, Andres; Hadnott, Bailey N; Awad, Andrew M; Herkert, Nicholas J; Tomsho, Kathryn; Basra, Komal; Scammell, Madeleine K; Heiger-Bernays, Wendy; Hornbuckle, Keri C

2017-04-11

Qualitatively and quantitatively, we have demonstrated that airborne polychlorinated biphenyl (PCB) concentrations in the air surrounding New Bedford Harbor (NBH) are caused by its water PCB emissions. We measured airborne PCBs at 18 homes and businesses near NBH in 2015, with values ranging from 0.4 to 38 ng m -3 , with a very strong Aroclor 1242/1016 signal that is most pronounced closest to the harbor and reproducible over three sampling rounds. Using U.S. Environmental Protection Agency (U.S. EPA) water PCB data from 2015 and local meteorology, we predicted gas-phase fluxes of PCBs from 160 to 1200 μg m -2 day -1 . Fluxes were used as emissions for AERMOD, a widely applied U.S. EPA atmospheric dispersion model, to predict airborne PCB concentrations. The AERMOD predictions were within a factor of 2 of the field measurements. PCB emission from NBH (110 kg year -1 , average 2015) is the largest reported source of airborne PCBs from natural waters in North America, and the source of high ambient air PCB concentrations in locations close to NBH. It is likely that NBH has been an important source of airborne PCBs since it was contaminated with Aroclors more than 60 years ago.

Concentration and characteristics of depleted uranium in water, air and biological samples collected in Serbia and Montenegro.

PubMed

Jia, Guogang; Belli, Maria; Sansone, Umberto; Rosamilia, Silvia; Gaudino, Stefania

2005-09-01

During the Balkan conflicts, in 1995 and 1999, depleted uranium (DU) rounds were employed and were left in the battlefield. Health concern is related to the risk arising from contamination of the environment with DU penetrators and dust. In order to evaluate the impact of DU on the environment and population in Serbia and Montenegro, radiological surveys of DU in water, air and biological samples were carried out over the period 27 October-5 November 2001. The uranium isotopic concentrations in biological samples collected in Serbia and Montenegro, mainly lichens and barks, were found to be in the range of 0.67-704 Bqkg(-1) for (238)U, 0.48-93.9 Bqkg(-1) for (234)U and 0.02-12.2 Bqkg(-1) for (235)U, showing uranium levels to be higher than in the samples collected at the control sites. Moreover, (236)U was detectable in some of the samples. The isotopic ratios of (234)U/(238)U showed DU to be detectable in many biological samples at all examined sites, especially in Montenegro, indicating widespread ground-surface DU contamination, albeit at very low level. The uranium isotopic concentrations in air obtained from the air filter samples collected in Serbia and Montenegro were found to be in the range of 1.99-42.1 microBqm(-3) for (238)U, 0.96-38.0 microBqm(-3) for (234)U, and 0.05-1.83 microBqm(-3) for (235)U, being in the typical range of natural uranium values. Thus said, most of the air samples are DU positive, this fact agreeing well with the widespread DU contamination detected in the biological samples. The uranium concentrations in water samples collected in Serbia and Montenegro were found to be in the range of 0.40-21.9 mBql(-1) for (238)U, 0.27-28.1 mBql(-1) for (234)U, and 0.01-0.88 mBql(-1) for (235)U, these values being much lower than those in mineral water found in central Italy and below the WHO guideline for drinking water. From a radiotoxicological point of view, at this moment there is no significant radiological risk related to these investigated

Indoor air quality in university classrooms and relative environment in terms of mass concentrations of particulate matter.

PubMed

Gaidajis, George; Angelakoglou, Komninos

2009-10-01

The mass concentrations of coarse (PM10) and fine (PM2.5) particulate matter were measured in different classrooms and relevant indoors areas of Democritus University, School of Engineering, Xanthi, with portable aerosol monitoring equipment. Two sampling campaigns were conducted in different seasons. The results indicated that the average concentrations in classrooms ranged from 32-188 microg/m3 and 25-151 microg/m3 for PM10 and PM2.5, respectively. Concentration levels above 300 microg/m3 were usually recorded, while the PM2.5/PM10 ratio was about 0.8. As expected, PM10 and PM2.5 average concentrations were significantly higher in the open-access meeting place of common use, indicating the significance of student trespassing and occasional smoking in the deterioration of indoors air quality.

Manganese concentrations in the air of the Montreal (Canada) subway in relation to surface automobile traffic density.

PubMed

Boudia, Nacéra; Halley, Renée; Kennedy, Greg; Lambert, Jean; Gareau, Lise; Zayed, Joseph

2006-07-31

Methylcyclopentadienyl manganese tricarbonyl (MMT) is an organic derivative of manganese (Mn), used since 1976 in Canadian gasoline as an octane enhancer. Its combustion leads to the emission of Mn particles. Several studies carried out by our research group have established a correlation between atmospheric Mn concentrations and automobile traffic density, suggesting that MMT in gasoline could play a significant role. This study aims to measure Mn concentrations in the air of the underground subway in Montreal (Canada) and to examine the relation with nearby surface automobile traffic density and, by extension, with the use of MMT in gasoline. Three subway stations were chosen for their location in different microenvironments with different traffic densities. Respirable (MnR<5 microm) and total Mn (MnT) were sampled over two weeks, 5 days/week, 12 h/day. For the station located in the lower traffic density area, relatively low levels of MnR and MnT were found, with averages of 0.018 and 0.032 microg/m(3), respectively. These concentrations are within the range of the background levels in Montreal. For the other two stations, the average concentrations of MnR were twice as high and exceeded the US EPA reference concentration of 0.05 microg/m(3). Although there may be several sources of Mn from different components of the subway structure and vehicles, no correlation was found between subway traffic and atmospheric Mn in the subway. Since the air in the underground subway is pumped directly from outside without filtration, our findings strongly suggest that the combustion of MMT in automobiles is an important factor.

Ada Compiler Validation Summary Report. Certificate Number 880728S1. 09141 DDC-I, Inc., DACS-386/UNIX, Version 4.2, ICL DRS 300 Host and Target

DTIC Science & Technology

1988-07-28

r R ~l~ F COPV en Data Entered) AT ION PAGE -ErOP RCoMrE-EoNGFOP. A D-A 204 928 1Z. GOVT ACCESSION NO. 3. RECIPIENT’S CATALOG NUMBER 4...PAGE (When Data Entered) Ada Compiler Validation Summary Repor-: Compiler Name: DACS-386/UNIX, Version 4.2 Certificate Number: 880728S1.09141 Host...which have the STORAGE SIZE length clause were changed to comment lines under the direction of the AVF Manager . These modified tests ran to a successful

Effect of non-surgical periodontal therapy on the concentration of volatile sulfur compound in mouth air of a group of nigerian young adults.

PubMed

Ehizele, Ao; Akhionbare, O

2013-07-01

The major goal of non-surgical periodontal therapy is to reduce or eliminate the subgingival pathogenic microbial flora that is known to be associated with volatile sulfur compounds (VSC). The aim of this study was, therefore, to determine the effect of non-surgical periodontal therapy on the concentration of VSC in mouth air of young adults. Four hundred subjects, grouped into two based on the absence or presence of periodontal diseases, were involved in this study. Basic periodontal examination was used for the grouping. The measurement of the concentration of the VSC in the mouth air of the subjects was done objectively, using the Halimeter, before and after the therapy, and at recall visits 2 weeks and 6 weeks after therapy. Chi-square and Paired t-test were used to find statistical significance. The results revealed that at baseline, 78.7% (48/61) of the subjects who had VSC concentration more than 250 parts per billion (ppb) were from the group with periodontal disease. Immediately after non-surgical periodontal therapy, only 8.5% (17/200) of the subjects with periodontal disease had VSC concentration of more than 250 ppb while all the subjects with no periodontal disease had VSC concentration less than 181 ppb. The same pattern of reduction in the concentration of the VSC and improvement in oral hygiene was also obtained 2 weeks and 6 weeks after therapy. It can be concluded that non-surgical periodontal therapy brought about reduction in the concentration of volatile sulfur compounds in mouth air of young adults.

Observation of Elevated Air Pollutant Concentrations in a Residential Neighborhood of Los Angeles California Using a Mobile Platform

PubMed Central

Hu, Shishan; Fruin, Scott; Kozawa, Kathleen; Mara, Steve; Winer, Arthur M.

2013-01-01

We observed elevated air pollutant concentrations, especially of ultrafine particles (UFP), black carbon (BC) and NO, across the residential neighborhood of the Boyle Heights Community (BH) of Los Angeles, California. Using an electric vehicle mobile platform equipped with fast response instruments, real-time air pollutant concentrations were measured in BH in spring and summer of 2008. Pollutant concentrations varied significantly in the two seasons, on different days, and by time of day, with an overall average UFP concentration in the residential areas of ~33 000 cm−3. The averaged UFP, BC, and NO concentrations measured on Soto St, a major surface street in BH, were 57 000 cm−3, 5.1 µg m−3, and 67 ppb, respectively. Concentrations of UFP across the residential areas in BH were nearly uniform spatially, in contrast to other areas in the greater metropolitan area of Los Angeles where UFP concentrations exhibit strong gradients downwind of roadways. We attribute this “UFP cloud” to high traffic volumes, including heavy duty diesel trucks on the freeways which surround and traverse BH, and substantial numbers of high-emitting vehicles (HEVs) on the surface streets traversing BH. Additionally, the high density of stop signs and lights and short block lengths, requiring frequent accelerations of vehicles, may contribute. The data also support a role for photochemical production of UFP in the afternoon. UFP concentration peaks (5 s average) of up to 9 million particles cm−3 were also observed immediately behind HEVs when they accelerated from stop lights in the BH neighborhood and areas immediately adjacent. Although encounters with HEV during mornings accounted for only about 6% and 17% of time spent monitoring residential areas and major surface streets, HEV contributed to about 28% and 53% of total ultrafine particles measured on the route, respectively. The observation of elevated pollutant number concentrations across the Boyle Heights community

Observation of elevated air pollutant concentrations in a residential neighborhood of Los Angeles California using a mobile platform

NASA Astrophysics Data System (ADS)

Hu, Shishan; Paulson, Suzanne E.; Fruin, Scott; Kozawa, Kathleen; Mara, Steve; Winer, Arthur M.

2012-05-01

We observed elevated air pollutant concentrations, especially of ultrafine particles (UFP), black carbon (BC) and NO, across the residential neighborhood of the Boyle Heights Community (BH) of Los Angeles, California. Using an electric vehicle mobile platform equipped with fast response instruments, real-time air pollutant concentrations were measured in BH in spring and summer of 2008. Pollutant concentrations varied significantly in the two seasons, on different days, and by time of day, with an overall average UFP concentration in the residential areas of ∼33 000 cm-3. The averaged UFP, BC, and NO concentrations measured on Soto St, a major surface street in BH, were 57 000 cm-3, 5.1 μg m-3, and 67 ppb, respectively. Concentrations of UFP across the residential areas in BH were nearly uniform spatially, in contrast to other areas in the greater metropolitan area of Los Angeles where UFP concentrations exhibit strong gradients downwind of roadways. We attribute this “UFP cloud” to high traffic volumes, including heavy duty diesel trucks on the freeways which surround and traverse BH, and substantial numbers of high-emitting vehicles (HEVs) on the surface streets traversing BH. Additionally, the high density of stop signs and lights and short block lengths, requiring frequent accelerations of vehicles, may contribute. The data also support a role for photochemical production of UFP in the afternoon. UFP concentration peaks (5 s average) of up to 9 million particles cm-3 were also observed immediately behind HEVs when they accelerated from stop lights in the BH neighborhood and areas immediately adjacent. Although encounters with HEV during mornings accounted for only about 6% and 17% of time spent monitoring residential areas and major surface streets, HEV contributed to about 28% and 53% of total ultrafine particles measured on the route, respectively. The observation of elevated pollutant concentrations across the Boyle Heights community highlights

Detrusor after-contraction: a new insight.

PubMed

Valentini, Francoise A; Marti, Brigitte G; Robain, Gilberte; Nelson, Pierre P

2015-01-01

Detrusor after-contractions (DAC) are non-common in adults. Both definition (nothing in ICS reports) and significance (artefact, link with detrusor overactivity (DO) or bladder outlet obstruction (BOO)) remain discussed. Our purpose was to carry out an analysis of the urodynamic parameters during voidings with DAC and, using the VBN model, to simulate pathophysiological conditions able to explain both voiding phase and DAC. From large urodynamic database of patients referred for evaluation of lower urinary tract dysfunction, DAC were observed in 60 patients (5.7%). Criteria for DAC were post-void residual <30mL and increase of detrusor pressure >10cmH(2)O. VBN model was used for analysis of both pressure and flow curves, and simulations of pathophysiological conditions. Onset of DAC (ODAC) occurred when Q=7.3±5.7mL/s and bladder volume=17.9±15.4mL. Urgency-frequency syndrome and urodynamic diagnosis of DO were the more frequent scenarios associated with DAC. ODAC was associated to an inversion of the slope of detrusor pressure curve without any perturbation in flow curve. Among tested pathophysiological hypothesis (great, abnormal, detrusor force, sphincter contraction), none allowed restoring all recorded curves (flow rate, voiding pressure and DAC). No urodynamic characteristic of the first part of voiding is an index of occurrence of DAC. ODAC is a significant phenomenon linked with the bladder collapse. DAC is not associated with BOO but more probably with DO and appears as the result of local conditions in an almost empty bladder (concentration of stresses around a transducer); thus DAC seems of weak clinical significance.

The influence of air-suspended particulate concentration on the incidence of suicide attempts and exacerbation of schizophrenia

NASA Astrophysics Data System (ADS)

Yackerson, Naomy S.; Zilberman, Arkadi; Todder, Doron; Kaplan, Zeev

2014-01-01

The main objective of this study was to evaluate the role of the concentration of solid air-suspended particles (SSP) in the incidence of mental disorders. The study is based on 1,871 cases, registered in the Beer-Sheva Mental Health Center (BS-MHC) at Ben-Gurion University (Israel) during a 16-month period from 2001 to 2002; 1,445 persons were hospitalized due to exacerbation of schizophrenia (ICD-10: F20-F29) and 426 after committing a suicide attempt using a variety of means as coded in the ICD-10 (ICD-10: X60-X84). Pearson and Spearman test correlations were used; the statistical significance was tested at p < 0.1. A significant correlation between variations of SSP number concentration ( N C ) during eastern desert wind during early morning hours and number of suicide attempts, N SU , was found ( ρ > 0.3, p < 0.05), whereas correlation between N C and N SU during western air streams (sea breeze) was not observed ( p > 0.2). A trend towards positive correlation ( ρ > 0.2, p < 0.1) between the N C and number of persons with exacerbation of schizophrenia as manifested in psychotic attack ( N PS ) in periods with dominant eastern winds (4-9 am, local time) has been observed, while in the afternoon and evening hours (1-8 pm local time) with dominant western winds, N C and N PS are not correlated (p > 0.1). Obviously, concentration of SSP is not the one and only parameter of air pollution state determining meteorological-biological impact, involving incidence of mental disorders, although its role can scarcely be overstated. However, since it is one of the simplest measured parameters, it could be widely used and helpful in the daily struggle for human life comfort in semi-arid areas as well as urban and industrial surroundings, where air pollution reaches crucial values. This study may permit determination of the limits for different external factors, which do not overcome threshold values (without provoking avalanche situations), to single out the group of

SciDAC's Earth System Grid Center for Enabling Technologies Semiannual Progress Report October 1, 2010 through March 31, 2011

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

Williams, Dean N.

2011-04-02

This report summarizes work carried out by the Earth System Grid Center for Enabling Technologies (ESG-CET) from October 1, 2010 through March 31, 2011. It discusses ESG-CET highlights for the reporting period, overall progress, period goals, and collaborations, and lists papers and presentations. To learn more about our project and to find previous reports, please visit the ESG-CET Web sites: http://esg-pcmdi.llnl.gov/ and/or https://wiki.ucar.edu/display/esgcet/Home. This report will be forwarded to managers in the Department of Energy (DOE) Scientific Discovery through Advanced Computing (SciDAC) program and the Office of Biological and Environmental Research (OBER), as well as national and international collaborators andmore » stakeholders (e.g., those involved in the Coupled Model Intercomparison Project, phase 5 (CMIP5) for the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report (AR5); the Community Earth System Model (CESM); the Climate Science Computational End Station (CCES); SciDAC II: A Scalable and Extensible Earth System Model for Climate Change Science; the North American Regional Climate Change Assessment Program (NARCCAP); the Atmospheric Radiation Measurement (ARM) program; the National Aeronautics and Space Administration (NASA), the National Oceanic and Atmospheric Administration (NOAA)), and also to researchers working on a variety of other climate model and observation evaluation activities. The ESG-CET executive committee consists of Dean N. Williams, Lawrence Livermore National Laboratory (LLNL); Ian Foster, Argonne National Laboratory (ANL); and Don Middleton, National Center for Atmospheric Research (NCAR). The ESG-CET team is a group of researchers and scientists with diverse domain knowledge, whose home institutions include eight laboratories and two universities: ANL, Los Alamos National Laboratory (LANL), Lawrence Berkeley National Laboratory (LBNL), LLNL, NASA/Jet Propulsion Laboratory (JPL), NCAR, Oak Ridge

Hourly pattern of allergenic alder and birch pollen concentrations in the air: Spatial differentiation and the effect of meteorological conditions

NASA Astrophysics Data System (ADS)

Borycka, K.; Kasprzyk, I.

2018-06-01

In temperate climate widespread alder and birch are an important source of strong aeroallergens. The diurnal pattern of airborne pollen concentrations depends on the rhythm of pollen release from anthers as well as weather conditions, convection air currents, long-distance transport, pollen trap location and local vegetation. The aim of the study was to present a diurnal pattern of Alnus (alder) and Betula (birch) pollen concentrations in the air in a horizontal and vertical gradient and examine the weather parameters that had the greatest impact on the pattern. The study was conducted in Rzeszów City, southeast Poland over three years. Pollen grains were collected using a Hirst volumetric spore trap at three sampling points: two at 12 m the agl, and one at 1.5 m agl. Data were analysed using circular statistics and a nonlinear function. For alder, three models of hourly patterns were elaborated and the most common presented early morning minimum and early afternoon maximum. For birch, the most common model has one peak at night and a marked decrease in concentrations in early morning, although a second model has peak during early afternoon. A model with 3 peaks is much less common. These models are characteristic for warm temperate climate regions, where alders and birches are common. The diurnal patterns did not depend on the localization of traps or proximity of the pollen source, although these factors influenced the hourly concentrations, with higher values observed at roof level. Significant relationships between the hourly pollen counts and meteorological parameters were observed only for alder. Three incidents of increasing birch pollen concentrations were observed during the first two hours of precipitation and linked to a convection effect. Unstable weather conditions caused by air convection might strongly modify the circadian pattern and cause the nightly peaks concentrations. The general results are that people suffering from allergies may be exposed

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.

Ambient concentrations and personal exposure to polycyclic aromatic hydrocarbons (PAH) in an urban community with mixed sources of air pollution.

PubMed

Zhu, Xianlei; Fan, Zhihua Tina; Wu, Xiangmei; Jung, Kyung Hwa; Ohman-Strickland, Pamela; Bonanno, Linda J; Lioy, Paul J

2011-01-01

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.

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

On-line monitoring of benzene air concentrations while driving in traffic by means of isotopic dilution gas chromatography/mass spectrometry.

PubMed

Davoli, E; Cappellini, L; Moggi, M; Ferrari, S; Fanelli, R

1996-01-01

There is no shortage of information about the average benzene concentrations in urban air, but there is very little about microenvironmental exposure, such as in-vehicle concentrations while driving in various traffic conditions, while refuelling, or while in a parking garage. The main reason for this lack of data is that no analytical instrumentation has been available to measure on-line trace amounts of benzene in such situations. We have recently proposed a highly accurate, high-speed cryofocusing gas chromatography/mass spectrometry (GC/MS) system for monitoring benzene concentrations in air. Accuracy of the analytical data is achieved by enrichment of the air sample before trapping, with a stable isotope permeation tube system. The same principles have been applied to a new instrument, specifically designed for operation on an electric vehicle (Ducato Elettra, Fiat). The zero emission vehicle and the fully transportable, battery-operated GC/MS system provide a unique possibility of monitoring benzene exposure in real everyday situations such as while driving, refuelling, or repairing a car. All power consumptions have been reduced so as to achieve a battery-operated GC/MS system. Liquid nitrogen cryofocusing has been replaced by a packed, inductively heated, graphitized charcoal microtrap. The instrument has been mounted on shock absorbers and installed in the van. The whole system has been tested in both fixed and mobile conditions. The maximum monitoring period without external power supply is 6 h. The full analytical cycle is 4 min, allowing close to real-time monitoring, and the minimum detectable level is 1 microgram/m3 for benzene. In-vehicle monitoring showed that, when recirculation was off and ventilation on, i.e., air from outside the vehicle was blown inside, concentrations varied widely in different driving conditions: moving from a parking lot into normal traffic on an urban traffic condition roadway yielded an increase in benzene concentration

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...

INDOOR AIR CONCENTRATIONS OF ORGANOCHLORINE, ORGANOPHOSPHATE AND PYRETHROID PESTICIDES IN THE US: FOUR STUDIES, SIX STATES AND TWENTY YEARS

EPA Science Inventory

Pesticides used to control indoor pests have transitioned across the chemicals classes of organochlorine, organophosphate, and pyrethroid compounds from the 1980's to the present. This work summarizes the pesticide concentrations measured from the indoor air of homes from four st...

Prediction of hydrodynamics and chemistry of confined turbulent methane-air frames in a two concentric tube combustor

NASA Technical Reports Server (NTRS)

Markatos, N. C.; Spalding, D. B.; Srivatsa, S. K.

1978-01-01

A formulation of the governing partial differential equations for fluid flow and reacting chemical species in a two-concentric-tube combustor is presented. A numerical procedure for the solution of the governing differential equations is described and models for chemical-equilibrium and chemical-kinetics calculations are presented. The chemical-equilibrium model is used to characterize the hydrocarbon reactions. The chemical-kinetics model is used to predict the concentrations of the oxides of nitrogen. The combustor considered consists of two coaxial ducts. Concentric streams of gaseous fuel and air enter the inlet duct at one end; the flow then reverses and flows out through the outer duct. Two sample cases with specified inlet and boundary conditions are considered and the results are discussed.

Concentration and movement of neonicotinoids as particulate matter downwind during agricultural practices using air samplers in southwestern Ontario, Canada.

PubMed

Forero, Luis Gabriel; Limay-Rios, Victor; Xue, Yingen; Schaafsma, Arthur

2017-12-01

Atmospheric emissions of neonicotinoid seed treatment insecticides as particulate matter in field crops occur mainly for two reasons: 1) due to abraded dust of treated seed generated during planting using vacuum planters, and 2) as a result of disturbances (tillage or wind events) in the surface of parental soils which release wind erodible soil-bound residues. In the present study, concentration and movement of neonicotinoids as particulate matter were quantified under real conditions using passive and active air samplers. Average neonicotinoid concentrations in Total Suspended Particulate (TSP) using passive samplers were 0.48 ng/cm 2 , trace, trace (LOD 0.80 and 0.04 ng/cm 2 for clothianidin and thiamethoxam, respectively), and using active samplers 16.22, 1.91 and 0.61 ng/m 3 during planting, tillage and wind events, respectively. There was a difference between events on total neonicotinoid concentration collected in particulate matter using either passive or active sampling. Distance of sampling from the source field during planting of treated seed had an effect on total neonicotinoid air concentration. However, during tillage distance did not present an effect on measured concentrations. Using hypothetical scenarios, values of contact exposure for a honey bee were estimated to be in the range from 1.1% to 36.4% of the reference contact LD 50 value of clothianidin of 44 ng/bee. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spatial and temporal variation in endotoxin and PM10 concentrations in ambient air in a livestock dense area.

PubMed

de Rooij, Myrna M T; Heederik, Dick J J; Borlée, Floor; Hoek, Gerard; Wouters, Inge M

2017-02-01

Several studies have reported associations between farming and respiratory health in neighboring residents. Health effects are possibly linked to fine dust and endotoxin emissions from livestock farms. Little is known about levels of these air pollutants in ambient air in livestock dense areas. We aimed to explore temporal and spatial variation of PM10 and endotoxin concentrations, and the association with livestock-related spatial and meteorological temporal determinants. From March till September 2011, one week average PM10 samples were collected using Harvard Impactors at eight sites (residential gardens) representing a variety of nearby livestock-related characteristics. A background site was included in the study area, situated at least 500m away from the nearest farm. PM10 mass was determined by gravimetric analysis and endotoxin level by means of Limulus-Amebocyte-Lysate assay. Data were analyzed using mixed models. The range between sites of geometric mean concentrations was for PM10 19.8-22.3µg/m 3 and for endotoxin 0.46-0.66EU/m 3 . PM10 concentrations and spatial variation were very similar for all sites, while endotoxin concentrations displayed a more variable pattern over time with larger differences between sites. Nonetheless, the temporal pattern at the background location was highly comparable to the sites mean temporal pattern both for PM10 and endotoxin (Pearson correlation: 0.92, 0.62). Spatial variation was larger for endotoxin than for PM10 (within/between site variance ratio: 0.63, 2.03). Spatial livestock-related characteristics of the surroundings were more strongly related to endotoxin concentrations, while temporal determinants were more strongly related to PM10 concentrations. The effect of local livestock-related sources on PM10 concentration was limited in this study carried out in a livestock dense area. The effect on endotoxin concentrations was more profound. To gain more insight in the effect of livestock-related sources on ambient

Air Quality System (AQS)

EPA Pesticide Factsheets

The Air Quality System (AQS) database contains measurements of air pollutant concentrations from throughout the United States and its territories. The measurements include both criteria air pollutants and hazardous air pollutants.

Measurement of cytoplasmic Ca2+ concentration in Saccharomyces cerevisiae induced by air cold plasma

NASA Astrophysics Data System (ADS)

Xiaoyu, DONG

2018-03-01

In this study, a novel approach to measure the absolute cytoplasmic Ca2+ concentration ([Ca2+]cyt) using the Ca2+ indicator fluo-3 AM was established. The parameters associated with the probe fluo-3 AM were optimized to accurately determine fluorescence intensity from the Ca2+-bound probe. Using three optimized parameters (final concentration of 6 mM probe, incubation time of 135 min, loading probe before plasma treatment), the maximum fluorescence intensity (F max = 527.8 a.u.) and the minimum fluorescence intensity (F min = 63.8 a.u.) were obtained in a saturated Ca2+ solution or a solution of lacking Ca2+. Correspondingly, the maximum [Ca2+]cyt induced by cold plasma was 1232.5 nM. Therefore, the Ca2+ indicator fluo-3 AM was successfully applied to measure the absolute [Ca2+]cyt in Saccharomyces cerevisiae stimulated by cold plasma at atmospheric air pressure.

Effect of Non-Surgical Periodontal Therapy on the Concentration of Volatile Sulfur Compound in Mouth Air of a Group of Nigerian Young Adults

PubMed Central

Ehizele, AO; Akhionbare, O

2013-01-01

Background: The major goal of non-surgical periodontal therapy is to reduce or eliminate the subgingival pathogenic microbial flora that is known to be associated with volatile sulfur compounds (VSC). Aim: The aim of this study was, therefore, to determine the effect of non-surgical periodontal therapy on the concentration of VSC in mouth air of young adults. Subjects and Methods: Four hundred subjects, grouped into two based on the absence or presence of periodontal diseases, were involved in this study. Basic periodontal examination was used for the grouping. The measurement of the concentration of the VSC in the mouth air of the subjects was done objectively, using the Halimeter, before and after the therapy, and at recall visits 2 weeks and 6 weeks after therapy. Chi-square and Paired t-test were used to find statistical significance. Results: The results revealed that at baseline, 78.7% (48/61) of the subjects who had VSC concentration more than 250 parts per billion (ppb) were from the group with periodontal disease. Immediately after non-surgical periodontal therapy, only 8.5% (17/200) of the subjects with periodontal disease had VSC concentration of more than 250 ppb while all the subjects with no periodontal disease had VSC concentration less than 181 ppb. The same pattern of reduction in the concentration of the VSC and improvement in oral hygiene was also obtained 2 weeks and 6 weeks after therapy. Conclusion: It can be concluded that non-surgical periodontal therapy brought about reduction in the concentration of volatile sulfur compounds in mouth air of young adults. PMID:24116328

Atmospheric concentrations, distributions and air-soil exchange tendencies of PAHs and PCBs in a heavily industrialized area in Kocaeli, Turkey.

PubMed

Cetin, Banu; Yurdakul, Sema; Keles, Melek; Celik, Isil; Ozturk, Fatma; Dogan, Cevdet

2017-09-01

Dilovasi is one of the heavily industrialized areas in Turkey with serious environmental problems. In this study, the atmospheric concentration of PAHs and PCBs were measured for a whole year at 23 sites. The average ambient air Σ 15 PAH and Σ 41 PCB concentrations were found as 285 ± 431 ng m -3 and 4152 ± 6072 pg m -3 , respectively. PAH concentrations increased with decreasing temperature especially in urban areas, indicating the impact of residential heating. However, PCB concentrations mostly increased with temperature probably due to enhanced volatilization from their sources. The gradient obtained for PCBs, rural < suburban < urban < industrial/urban, is more clear than those obtained for PAHs. The average Σ 15 PAH and Σ 41 PCB soil concentrations were found as 992 ± 1323 and 18.8 ± 32.0 μg kg -1 , respectively. PCB soil concentrations did not show significant temporal variations while PAH concentrations were variable especially for urban areas. The volatilization tendencies of low and medium molecular weight PAHs from soil to air were higher in industrial-urban areas than rural sites, showing that soil was a secondary source for PAHs. Fugacity ratios of PCBs were mostly <1.0 for the whole sampling period. Although the source/sink tendency of soil for some PCBs depends on their volatility, considering the whole data, PCBs were generally deposited to soil. Copyright © 2017 Elsevier Ltd. All rights reserved.

Intercomparison of air quality data using principal component analysis, and forecasting of PM₁₀ and PM₂.₅ concentrations using artificial neural networks, in Thessaloniki and Helsinki.

PubMed

Voukantsis, Dimitris; Karatzas, Kostas; Kukkonen, Jaakko; Räsänen, Teemu; Karppinen, Ari; Kolehmainen, Mikko

2011-03-01

In this paper we propose a methodology consisting of specific computational intelligence methods, i.e. principal component analysis and artificial neural networks, in order to inter-compare air quality and meteorological data, and to forecast the concentration levels for environmental parameters of interest (air pollutants). We demonstrate these methods to data monitored in the urban areas of Thessaloniki and Helsinki in Greece and Finland, respectively. For this purpose, we applied the principal component analysis method in order to inter-compare the patterns of air pollution in the two selected cities. Then, we proceeded with the development of air quality forecasting models for both studied areas. On this basis, we formulated and employed a novel hybrid scheme in the selection process of input variables for the forecasting models, involving a combination of linear regression and artificial neural networks (multi-layer perceptron) models. The latter ones were used for the forecasting of the daily mean concentrations of PM₁₀ and PM₂.₅ for the next day. Results demonstrated an index of agreement between measured and modelled daily averaged PM₁₀ concentrations, between 0.80 and 0.85, while the kappa index for the forecasting of the daily averaged PM₁₀ concentrations reached 60% for both cities. Compared with previous corresponding studies, these statistical parameters indicate an improved performance of air quality parameters forecasting. It was also found that the performance of the models for the forecasting of the daily mean concentrations of PM₁₀ was not substantially different for both cities, despite the major differences of the two urban environments under consideration. Copyright © 2011 Elsevier B.V. All rights reserved.

A rapid culture system uninfluenced by an inoculum effect increases reliability and convenience for drug susceptibility testing of Mycobacterium tuberculosis.

PubMed

Jung, Yong-Gyun; Kim, Hyejin; Lee, Sangyeop; Kim, Suyeoun; Jo, EunJi; Kim, Eun-Geun; Choi, Jungil; Kim, Hyun Jung; Yoo, Jungheon; Lee, Hye-Jeong; Kim, Haeun; Jung, Hyunju; Ryoo, Sungweon; Kwon, Sunghoon

2018-06-05

The Disc Agarose Channel (DAC) system utilizes microfluidics and imaging technologies and is fully automated and capable of tracking single cell growth to produce Mycobacterium tuberculosis (MTB) drug susceptibility testing (DST) results within 3~7 days. In particular, this system can be easily used to perform DSTs without the fastidious preparation of the inoculum of MTB cells. Inoculum effect is one of the major problems that causes DST errors. The DAC system was not influenced by the inoculum effect and produced reliable DST results. In this system, the minimum inhibitory concentration (MIC) values of the first-line drugs were consistent regardless of inoculum sizes ranging from ~10 3 to ~10 8 CFU/mL. The consistent MIC results enabled us to determine the critical concentrations for 12 anti-tuberculosis drugs. Based on the determined critical concentrations, further DSTs were performed with 254 MTB clinical isolates without measuring an inoculum size. There were high agreement rates (96.3%) between the DAC system and the absolute concentration method using Löwenstein-Jensen medium. According to these results, the DAC system is the first DST system that is not affected by the inoculum effect. It can thus increase reliability and convenience for DST of MTB. We expect that this system will be a potential substitute for conventional DST systems.

Concentric Split Flow Filter

NASA Technical Reports Server (NTRS)

Stapleton, Thomas J. (Inventor)

2015-01-01

A concentric split flow filter may be configured to remove odor and/or bacteria from pumped air used to collect urine and fecal waste products. For instance, filter may be designed to effectively fill the volume that was previously considered wasted surrounding the transport tube of a waste management system. The concentric split flow filter may be configured to split the air flow, with substantially half of the air flow to be treated traveling through a first bed of filter media and substantially the other half of the air flow to be treated traveling through the second bed of filter media. This split flow design reduces the air velocity by 50%. In this way, the pressure drop of filter may be reduced by as much as a factor of 4 as compare to the conventional design.

Occupational Exposure to Cobalt and Tungsten in the Swedish Hard Metal Industry: Air Concentrations of Particle Mass, Number, and Surface Area

PubMed Central

Bryngelsson, Ing-Liss; Pettersson, Carin; Husby, Bente; Arvidsson, Helena; Westberg, Håkan

2016-01-01

Exposure to cobalt in the hard metal industry entails severe adverse health effects, including lung cancer and hard metal fibrosis. The main aim of this study was to determine exposure air concentration levels of cobalt and tungsten for risk assessment and dose–response analysis in our medical investigations in a Swedish hard metal plant. We also present mass-based, particle surface area, and particle number air concentrations from stationary sampling and investigate the possibility of using these data as proxies for exposure measures in our study. Personal exposure full-shift measurements were performed for inhalable and total dust, cobalt, and tungsten, including personal real-time continuous monitoring of dust. Stationary measurements of inhalable and total dust, PM2.5, and PM10 was also performed and cobalt and tungsten levels were determined, as were air concentration of particle number and particle surface area of fine particles. The personal exposure levels of inhalable dust were consistently low (AM 0.15mg m−3, range <0.023–3.0mg m−3) and below the present Swedish occupational exposure limit (OEL) of 10mg m−3. The cobalt levels were low as well (AM 0.0030mg m−3, range 0.000028–0.056mg m−3) and only 6% of the samples exceeded the Swedish OEL of 0.02mg m−3. For continuous personal monitoring of dust exposure, the peaks ranged from 0.001 to 83mg m−3 by work task. Stationary measurements showed lower average levels both for inhalable and total dust and cobalt. The particle number concentration of fine particles (AM 3000 p·cm−3) showed the highest levels at the departments of powder production, pressing and storage, and for the particle surface area concentrations (AM 7.6 µm2·cm−3) similar results were found. Correlating cobalt mass-based exposure measurements to cobalt stationary mass-based, particle area, and particle number concentrations by rank and department showed significant correlations for all measures except for particle

Impact of CNG implementation on PAHs concentration in the ambient air of Delhi: a comparative assessment of pre- and post-CNG scenario.

PubMed

Khillare, P S; Agarwal, Tripti; Shridhar, Vijay

2008-12-01

The use of alternative fuel is considered to be an effective measure to improve the urban air quality. Concerned over deteriorating air quality in Delhi, the Delhi government initiated different measures including stringent emission norms, improved fuel quality and above all introduction of cleaner fuel-CNG in public transport system. The entire city bus fleet was converted to CNG mode by 2002. The present study reports the comparative assessment of the status of air quality with respect to PM(10) and PAH before and after the introduction of CNG in public transport system in Delhi. The study has been carried out for two different time periods: first in the year 1998 and second in the year 2004. Following the total conversion of public transport system to CNG in 2002, Post-CNG data indicate a sharp reduction of 51-74% in the PM(10) concentration and 58-68% in the TPAH concentration as compared to the Pre-CNG data.

Observational study on the concentration distributions of SO{sub 2} and NO{sub 2} in Dhaka, Bangladesh under severe air pollution condition in winter

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

Azad, A.K.; Kitada, T.

1996-12-31

Dhaka is the capital and the biggest city of Bangladesh, and is expanding very rapidly. Emissions from heavy traffic and many small industries and commercial complexes, newly developed in and around the city, are polluting the air of Dhaka city. The air pollution is severe especially in winter due to adverse meteorological conditions such as low wind speed and dry, stably-stratified air, which restricts the mixing height to low levels and prevent dispersion of pollutants. But so far no study of air pollution of Dhaka city has been done. We have first measured SO{sub 2} and NO{sub 2} concentrations inmore » Dhaka city in a large scale and derived their spatial distributions over Dhaka. Molecular diffusion tubes, which do not require power sources and are produced at low cost, have been used to measure the concentration distributions of SO{sub 2} and NO{sub 2} at 64 sites in Dhaka city and its suburbs during the period of December-January of 1995-96. The diffusion tube samplers were calibrated using 6 automated air pollution monitoring stations in Aichi-prefecture, Japan. The calibration curve and the distribution of the concentration data acquired by automatic measurement instrument at each location showed that the error range of measurements with the molecular diffusion tube samplers was 2-27%. The samples were analyzed using ion-chromatography and spectrophotometer to determine the concentrations of SO{sub 2} and NO{sub 2} respectively. The contamination of unexposed tubes under field conditions was determined and the value of the blank test was subtracted from the measurements of the diffusion tube samplers. The effects of wind turbulence and temperature were reduced using polyflon filters.« less

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.

Photoinitiated Polymerization of Cationic Acrylamide in Aqueous Solution: Synthesis, Characterization, and Sludge Dewatering Performance

PubMed Central

Zheng, Huaili; Liao, Yi; Zheng, Meizhen; Zhu, Chuanjun; Ji, Fangying; Ma, Jiangya; Fan, Wei

2014-01-01

A copolymer of acrylamide (AM) with acryloyloxyethyl trimethyl ammonium chloride (DAC) as the cationic monomer was synthesized under the irradiation of high-pressure mercury lamp with 2,2-azobis(2-amidinopropane) dihydrochloride (V-50) as the photoinitiator. The compositions of the photoinduced copolymer were characterized by Fourier transform infrared spectra (FTIR), ultraviolet spectra (UV), and scanning electron microscope (SEM). The effects of 6 important factors, that is, photo-initiators concentration, monomers concentration, CO(NH2)2 (urea) concentrations, pH value, mass ratio of AM to DAC, and irradiation time on the molecular weight and dissolving time, were investigated. The optimal reaction conditions were that the photo-initiators concentration was 0.3%, monomers concentration was 30 wt.%, irradiation time was 60 min, urea concentration was 0.4%, pH value was 5.0, and mass ratio of AM to DAC was 6 : 4. Its flocculation properties were evaluated with activated sludge using jar test. The zeta potential of supernatant at different cationic monomer contents was simultaneously measured. The results demonstrated the superiority of the copolymer over the commercial polyacrylamide as a flocculant. PMID:24683343

DAC-board based X-band EPR spectrometer with arbitrary waveform control

NASA Astrophysics Data System (ADS)

Kaufmann, Thomas; Keller, Timothy J.; Franck, John M.; Barnes, Ryan P.; Glaser, Steffen J.; Martinis, John M.; Han, Songi

2013-10-01

We present arbitrary control over a homogenous spin system, demonstrated on a simple, home-built, electron paramagnetic resonance (EPR) spectrometer operating at 8-10 GHz (X-band) and controlled by a 1 GHz arbitrary waveform generator (AWG) with 42 dB (i.e. 14-bit) of dynamic range. Such a spectrometer can be relatively easily built from a single DAC (digital to analog converter) board with a modest number of stock components and offers powerful capabilities for automated digital calibration and correction routines that allow it to generate shaped X-band pulses with precise amplitude and phase control. It can precisely tailor the excitation profiles "seen" by the spins in the microwave resonator, based on feedback calibration with experimental input. We demonstrate the capability to generate a variety of pulse shapes, including rectangular, triangular, Gaussian, sinc, and adiabatic rapid passage waveforms. We then show how one can precisely compensate for the distortion and broadening caused by transmission into the microwave cavity in order to optimize corrected waveforms that are distinctly different from the initial, uncorrected waveforms. Specifically, we exploit a narrow EPR signal whose width is finer than the features of any distortions in order to map out the response to a short pulse, which, in turn, yields the precise transfer function of the spectrometer system. This transfer function is found to be consistent for all pulse shapes in the linear response regime. In addition to allowing precise waveform shaping capabilities, the spectrometer presented here offers complete digital control and calibration of the spectrometer that allows one to phase cycle the pulse phase with 0.007° resolution and to specify the inter-pulse delays and pulse durations to ⩽250 ps resolution. The implications and potential applications of these capabilities will be discussed.

SciDAC GSEP: Gyrokinetic Simulation of Energetic Particle Turbulence and Transport

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

Lin, Zhihong

Energetic particle (EP) confinement is a key physics issue for burning plasma experiment ITER, the crucial next step in the quest for clean and abundant energy, since ignition relies on self-heating by energetic fusion products (α-particles). Due to the strong coupling of EP with burning thermal plasmas, plasma confinement property in the ignition regime is one of the most uncertain factors when extrapolating from existing fusion devices to the ITER tokamak. EP population in current tokamaks are mostly produced by auxiliary heating such as neutral beam injection (NBI) and radio frequency (RF) heating. Remarkable progress in developing comprehensive EP simulationmore » codes and understanding basic EP physics has been made by two concurrent SciDAC EP projects GSEP funded by the Department of Energy (DOE) Office of Fusion Energy Science (OFES), which have successfully established gyrokinetic turbulence simulation as a necessary paradigm shift for studying the EP confinement in burning plasmas. Verification and validation have rapidly advanced through close collaborations between simulation, theory, and experiment. Furthermore, productive collaborations with computational scientists have enabled EP simulation codes to effectively utilize current petascale computers and emerging exascale computers. We review here key physics progress in the GSEP projects regarding verification and validation of gyrokinetic simulations, nonlinear EP physics, EP coupling with thermal plasmas, and reduced EP transport models. Advances in high performance computing through collaborations with computational scientists that enable these large scale electromagnetic simulations are also highlighted. These results have been widely disseminated in numerous peer-reviewed publications including many Phys. Rev. Lett. papers and many invited presentations at prominent fusion conferences such as the biennial International Atomic Energy Agency (IAEA) Fusion Energy Conference and the annual meeting

Carbon-13 Isotopic Abundance and Concentration of Atmospheric Methane for Background Air in the Southern and Northern Hemispheres from 1978 to 1989 (NDP-049)

DOE Data Explorer

Stevens, C. M. [Chemical Technology Division, Argonne National Laboratory, Argonne, Illinois (USA)

2012-01-01

This data package presents atmospheric CH4 concentration and 13C isotopic abundance data derived from air samples collected over the period 1978-1989 at globally distributed clean-air sites. The data set comprises 201 records, 166 from the Northern Hemisphere and 35 from the Southern Hemisphere. The air samples were collected mostly in rural or marine locations remote from large sources of CH4 and are considered representative of tropospheric background conditions. The air samples were processed by isolation of CH4 from air and conversion to CO2 for isotopic analysis by isotope ratio mass spectrometry. These data represent one of the earliest records of 13C isotopic yy!measurements for atmospheric methane and have been used to refine estimates of CH4 emissions, calculate annual growth rates of emissions from changing sources, and provide evidence for changes in the rate of atmospheric removal of CH4. The data records consist of sample collection date; number of samples combined for analysis; sampling location; analysis date; CH4 concentration; 13C isotopic abundance; and flag codes to indicate outliers, repeated analyses, and other information.

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

Developmental Exposure to Concentrated Ambient Ultrafine Particulate Matter Air Pollution in Mice Results in Persistent and Sex-Dependent Behavioral Neurotoxicity and Glial Activation

PubMed Central

Allen, Joshua L.; Liu, Xiufang; Weston, Douglas; Prince, Lisa; Oberdörster, Günter; Finkelstein, Jacob N.; Johnston, Carl J.; Cory-Slechta, Deborah A.

2014-01-01

The brain appears to be a target of air pollution. This study aimed to further ascertain behavioral and neurobiological mechanisms of our previously observed preference for immediate reward (Allen, J. L., Conrad, K., Oberdorster, G., Johnston, C. J., Sleezer, B., and Cory-Slechta, D. A. (2013). Developmental exposure to concentrated ambient particles and preference for immediate reward in mice. Environ. Health Perspect. 121, 32–38), a phenotype consistent with impulsivity, in mice developmentally exposed to inhaled ultrafine particles. It examined the impact of postnatal and/or adult concentrated ambient ultrafine particles (CAPS) or filtered air on another behavior thought to reflect impulsivity, Fixed interval (FI) schedule-controlled performance, and extended the assessment to learning/memory (novel object recognition (NOR)), and locomotor activity to assist in understanding behavioral mechanisms of action. In addition, levels of brain monoamines and amino acids, and markers of glial presence and activation (GFAP, IBA-1) were assessed in mesocorticolimbic brain regions mediating these cognitive functions. This design produced four treatment groups/sex of postnatal/adult exposure: Air/Air, Air/CAPS, CAPS/Air, and CAPS/CAPS. FI performance was adversely influenced by CAPS/Air in males, but by Air/CAPS in females, effects that appeared to reflect corresponding changes in brain mesocorticolimbic dopamine/glutamate systems that mediate FI performance. Both sexes showed impaired short-term memory on the NOR. Mechanistically, cortical and hippocampal changes in amino acids raised the potential for excitotoxicity, and persistent glial activation was seen in frontal cortex and corpus callosum of both sexes. Collectively, neurodevelopment and/or adulthood CAPS can produce enduring and sex-dependent neurotoxicity. Although mechanisms of these effects remain to be fully elucidated, findings suggest that neurodevelopment and/or adulthood air pollution exposure may

Deriving realistic source boundary conditions for a CFD simulation of concentrations in workroom air.

PubMed

Feigley, Charles E; Do, Thanh H; Khan, Jamil; Lee, Emily; Schnaufer, Nicholas D; Salzberg, Deborah C

2011-05-01

Computational fluid dynamics (CFD) is used increasingly to simulate the distribution of airborne contaminants in enclosed spaces for exposure assessment and control, but the importance of realistic boundary conditions is often not fully appreciated. In a workroom for manufacturing capacitors, full-shift samples for isoamyl acetate (IAA) were collected for 3 days at 16 locations, and velocities were measured at supply grills and at various points near the source. Then, velocity and concentration fields were simulated by 3-dimensional steady-state CFD using 295K tetrahedral cells, the k-ε turbulence model, standard wall function, and convergence criteria of 10(-6) for all scalars. Here, we demonstrate the need to represent boundary conditions accurately, especially emission characteristics at the contaminant source, and to obtain good agreement between observations and CFD results. Emission rates for each day were determined from six concentrations measured in the near field and one upwind using an IAA mass balance. The emission was initially represented as undiluted IAA vapor, but the concentrations estimated using CFD differed greatly from the measured concentrations. A second set of simulations was performed using the same IAA emission rates but a more realistic representation of the source. This yielded good agreement with measured values. Paying particular attention to the region with highest worker exposure potential-within 1.3 m of the source center-the air speed and IAA concentrations estimated by CFD were not significantly different from the measured values (P = 0.92 and P = 0.67, respectively). Thus, careful consideration of source boundary conditions greatly improved agreement with the measured values.

Oxygen-Concentrating Cell

NASA Technical Reports Server (NTRS)

Buehler, K.

1986-01-01

High-purity oxygen produced from breathing air or from propellantgrade oxygen in oxygen-concentrating cell. Operating economics of concentrator attractive: Energy consumption about 4 Wh per liter of oxygen, slightly lower than conventional electrochemical oxygen extractors.

Defences against ammonia toxicity in tropical air-breathing fishes exposed to high concentrations of environmental ammonia: a review.

PubMed

Ip, Y K; Chew, S F; Wilson, J M; Randall, D J

2004-10-01

In the tropics, air-breathing fishes can be exposed to environmental ammonia when stranded in puddles of water during the dry season, during a stay inside a burrow, or after agricultural fertilization. At low concentrations of environmental ammonia, NH(3) excretion is impeded, as in aerial exposure, leading to the accumulation of endogenous ammonia. At high concentrations of environmental ammonia, which results in a reversed NH(3) partial pressure gradient (DeltaP(NH3)), there is retention of endogenous ammonia and uptake of exogenous ammonia. In this review, several tropical air-breathing fishes (giant mudskipper, African catfish, oriental weatherloach, swamp eel, four-eyed sleeper, abehaze and slender African lungfish), which can tolerate high environmental ammonia exposure, are used as examples to demonstrate how eight different adaptations can be involved in defence against ammonia toxicity. Four of these adaptations deal with ammonia toxicity at branchial and/or epithelial surfaces: (1) active excretion of NH(4)(+); (2) lowering of environmental pH; (3) low NH(3) permeability of epithelial surfaces; and (4) volatilization of NH(3), while another four adaptations ameliorate ammonia toxicity at the cellular and subcellular levels: (5) high tolerance of ammonia at the cellular and subcellular levels; (6) reduction in ammonia production; (7) glutamine synthesis; and (8) urea synthesis. The responses of tropical air-breathing fishes to high environmental ammonia are determined apparently by behavioural adaptations and the nature of their natural environments.

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.

“Modeling Trends in Air Pollutant Concentrations over the ...

EPA Pesticide Factsheets

Regional model calculations over annual cycles have pointed to the need for accurately representing impacts of long-range transport. Linking regional and global scale models have met with mixed success as biases in the global model can propagate and influence regional calculations and often confound interpretation of model results. Since transport is efficient in the free-troposphere and since simulations over Continental scales and annual cycles provide sufficient opportunity for “atmospheric turn-over”, i.e., exchange between the free-troposphere and the boundary-layer, a conceptual framework is needed wherein interactions between processes occurring at various spatial and temporal scales can be consistently examined. The coupled WRF-CMAQ model is expanded to hemispheric scales and model simulations over period spanning 1990-current are analyzed to examine changes in hemispheric air pollution resulting from changes in emissions over this period. The National Exposure Research Laboratory (NERL) Atmospheric Modeling and Analysis Division (AMAD) conducts research in support of EPA mission to protect human health and the environment. AMAD research program is engaged in developing and evaluating predictive atmospheric models on all spatial and temporal scales for forecasting the air quality and for assessing changes in air quality and air pollutant exposures, as affected by changes in ecosystem management and regulatory decisions. AMAD is responsible for pr

[Attempt to reduce the formaldehyde concentration by blowing cooled fresh air down in to the breathing zone of medical students from an admission port on the ceiling during gross anatomy class].

PubMed

Takayanagi, Masaaki; Sakai, Makoto; Ishikawa, Youichi; Murakami, Kunio; Kimura, Akihiko; Kakuta, Sachiko; Sato, Fumi

2008-09-01

Cadavers in gross anatomy laboratories at most medical schools are conventionally embalmed in formaldehyde solution, which is carcinogenic to humans. Medical students and instructors are thus exposed to formaldehyde vapors emitted from cadavers during dissection. To reduce high formaldehyde concentrations in the breathing zone above cadavers being examined by anatomy medical students provisionally, dissection beds were located under existing admission ports on the ceiling to supply cooled fresh air from the admission port blowing downward on to the cadaver. In all cases, compared to normal condition, the downward flow of cooled fresh air from an admission port reduced formaldehyde concentrations by 0.09-0.98 ppm and reduced to 12.6-65.4% in the air above a cadaver in the breathing zone of students. The formaldehyde concentrations above cadavers under admission ports were not more than the formaldehyde concentrations between beds representing the indoor formaldehyde concentrations. Although the application of an existing admission port on the ceiling in this study did not remove formaldehyde, the downflow of cooled fresh air using this system reduced the formaldehyde concentration in the air above cadavers being attended by anatomy students during dissections. These results suggest the need for reducing formaldehyde levels in gross anatomy laboratories using fundamental countermeasures in order to satisfy the guidelines of 0.08 ppm established by the World Health Organization and the Japan Ministry of Health, Labor and Welfare.

Secondhand smoke exposure and risk following the Irish smoking ban: an assessment of salivary cotinine concentrations in hotel workers and air nicotine levels in bars.

PubMed

Mulcahy, M; Evans, D S; Hammond, S K; Repace, J L; Byrne, M

2005-12-01

To investigate whether the Irish smoking ban has had an impact on secondhand smoke (SHS) exposures for hospitality workers. Before and after the smoking ban a cohort of workers (n = 35) from a sample of city hotels (n = 15) were tested for saliva cotinine concentrations and completed questionnaires. Additionally, a random sample (n = 20) of city centre bars stratified by size (range 400-5000 square feet), were tested for air nicotine concentrations using passive samplers before and after the ban. Salivary cotinine concentrations (ng/ml), duration of self reported exposures to secondhand smoke, air nicotine (microg/cubic metre). Cotinine concentrations reduced by 69%, from 1.6 ng/ml to 0.5 ng/ml median (SD 1.29; p < 0.005). Overall 74% of subjects experienced decreases (range 16-99%), with 60% showing a halving of exposure levels at follow up. Self reported exposure to SHS at work showed a significant reduction from a median 30 hours a week to zero (p < 0.001). There was an 83% reduction in air nicotine concentrations from median 35.5 microg/m3 to 5.95 microg/m3 (p < 0.001). At baseline, three bars (16%) were below the 6.8 microg/m3 air nicotine significant risk level for lung cancer alone; at follow up this increased to 10 (53%). Passive smoking and associated risks were significantly reduced but not totally eliminated. Exposure to SHS is still possible for those working where smoking is still allowed and those working where smoke may migrate from outdoor areas. Further research is required to assess the true extent and magnitude of these exposures.

Effects of air pollution on cell membrane integrity, spectral reflectance and metal and sulfur concentrations in lichens

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

Garty, J.; Cohen, Y.; Kloog, N.

1997-07-01

The fruticose lichen Ramalina duriaei is generally considered to be sensitive to air pollution. In the present study the authors sought to determine whether thalli of this lichen collected in a remote unpolluted site (the HaZorea Forest, northeast Israel) and transplanted to the Ashdod region (southwest Israel) could provide information on the quality of the air in this area. For this purpose, the concentrations of Pb, Cu, Cd, Ni, Mn, Fe, S, Ca, Mg, Na, and K were determined in in situ thalli collected in the HaZorea Forest in March 1993 and in in situ and transplanted thalli retrieved inmore » June 1993. The concentration of these elements in R. duriaei thalli was analyzed in comparison with physiological parameters such as the integrity of cell membranes, chlorophyll content, and alterations in reflectance responses from lichen thalli. Thalli transplanted to several industrial sites in the town of Ashdod for a period of 100 d accumulated high concentrations of Pb, Cd, Ni, Fe, S, Mg, Na, Ca, and K. The concentration of S in thalli transplanted to the Ashdod region was found to correlate with damage caused to cell membranes and showed and inverse correlation with the chlorophyll content and with the reflectance response of the lichen. The electrical conductivity values corresponding to membrane integrity in the lichen thallus showed an inverse correlation with the ratio of chlorophyll a to pheophytin a, indicating the integrity of the photobiontic chlorophyll and with normalized-difference vegetation index values corresponding to the reflectance response of the thallus. The chlorophyll integrity correlated with the reflectance response. Magnesium accumulated in the lichen thalli in dusty sites and was found to correlate with damage caused to membranes.« less

Assessing Concentrations and Health Impacts of Air Quality Management Strategies: Framework for Rapid Emissions Scenario and Health impact ESTimation (FRESH-EST)

PubMed Central

Milando, Chad W.; Martenies, Sheena E.; Batterman, Stuart A.

2017-01-01

In air quality management, reducing emissions from pollutant sources often forms the primary response to attaining air quality standards and guidelines. Despite the broad success of air quality management in the US, challenges remain. As examples: allocating emissions reductions among multiple sources is complex and can require many rounds of negotiation; health impacts associated with emissions, the ultimate driver for the standards, are not explicitly assessed; and long dispersion model run-times, which result from the increasing size and complexity of model inputs, limit the number of scenarios that can be evaluated, thus increasing the likelihood of missing an optimal strategy. A new modeling framework, called the "Framework for Rapid Emissions Scenario and Health impact ESTimation" (FRESH-EST), is presented to respond to these challenges. FRESH-EST estimates concentrations and health impacts of alternative emissions scenarios at the urban scale, providing efficient computations from emissions to health impacts at the Census block or other desired spatial scale. In addition, FRESH-EST can optimize emission reductions to meet specified environmental and health constraints, and a convenient user interface and graphical displays are provided to facilitate scenario evaluation. The new framework is demonstrated in an SO2 non-attainment area in southeast Michigan with two optimization strategies: the first minimizes emission reductions needed to achieve a target concentration; the second minimizes concentrations while holding constant the cumulative emissions across local sources (e.g., an emissions floor). The optimized strategies match outcomes in the proposed SO2 State Implementation Plan without the proposed stack parameter modifications or shutdowns. In addition, the lower health impacts estimated for these strategies suggest the potential for FRESH-EST to identify pollution control alternatives for air quality management planning. PMID:27318620

Assessing concentrations and health impacts of air quality management strategies: Framework for Rapid Emissions Scenario and Health impact ESTimation (FRESH-EST).

PubMed

Milando, Chad W; Martenies, Sheena E; Batterman, Stuart A

2016-09-01

In air quality management, reducing emissions from pollutant sources often forms the primary response to attaining air quality standards and guidelines. Despite the broad success of air quality management in the US, challenges remain. As examples: allocating emissions reductions among multiple sources is complex and can require many rounds of negotiation; health impacts associated with emissions, the ultimate driver for the standards, are not explicitly assessed; and long dispersion model run-times, which result from the increasing size and complexity of model inputs, limit the number of scenarios that can be evaluated, thus increasing the likelihood of missing an optimal strategy. A new modeling framework, called the "Framework for Rapid Emissions Scenario and Health impact ESTimation" (FRESH-EST), is presented to respond to these challenges. FRESH-EST estimates concentrations and health impacts of alternative emissions scenarios at the urban scale, providing efficient computations from emissions to health impacts at the Census block or other desired spatial scale. In addition, FRESH-EST can optimize emission reductions to meet specified environmental and health constraints, and a convenient user interface and graphical displays are provided to facilitate scenario evaluation. The new framework is demonstrated in an SO2 non-attainment area in southeast Michigan with two optimization strategies: the first minimizes emission reductions needed to achieve a target concentration; the second minimizes concentrations while holding constant the cumulative emissions across local sources (e.g., an emissions floor). The optimized strategies match outcomes in the proposed SO2 State Implementation Plan without the proposed stack parameter modifications or shutdowns. In addition, the lower health impacts estimated for these strategies suggest that FRESH-EST could be used to identify potentially more desirable pollution control alternatives in air quality management planning

Thoron, radon and air ions spatial distribution in indoor air.

PubMed

Kolarž, Predrag; Vaupotič, Janja; Kobal, Ivan; Ujić, Predrag; Stojanovska, Zdenka; Žunić, Zora S

2017-07-01

Spatial distribution of radioactive gasses thoron (Tn) and radon (Rn) in indoor air of 9 houses mostly during winter period of 2013 has been studied. According to properties of alpha decay of both elements, air ionization was also measured. Simultaneous continual measurements using three Rn/Tn and three air-ion active instruments deployed on to three different distances from the wall surface have shown various outcomes. It has turned out that Tn and air ions concentrations decrease with the distance increase, while Rn remained uniformly distributed. Exponential fittings function for Tn variation with distance was used for the diffusion length and constant as well as the exhalation rate determination. The obtained values were similar with experimental data reported in the literature. Concentrations of air ions were found to be in relation with Rn and obvious, but to a lesser extent, with Tn. Copyright © 2016 Elsevier Ltd. All rights reserved.

Measuring concentrations of selected air pollutants inside California vehicles. Final report

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

Rodes, C.; Sheldon, L.; Whitaker, D.

1999-01-01

This project measured 2-hour integrated concentrations of PM10, PM2.5, metals and a number of organic chemicals including benzene and MTBE inside vehicles on California roadways. Using continuous samplers, particle counts, black carbon, and CO were also measured. In addition to measuring in-vehicle levels, the investigators measured pollutant levels just outside the vehicle, at roadside stations, and ambient air monitoring stations. Different driving scenarios were designed to assess the effects of a number of factors on in-vehicle pollutant levels. These factors included roadway type, carpool lanes, traffic conditions, geographical locations, vehicle type, and vehicle ventilation conditions. The statewide average in-vehicle concentrationsmore » of benzene, MTBE, and formaldehyde ranged from 3--22 {micro}g/m{sup 3}, 3--90 {micro}g/m{sup 3}, and 0---22 {micro}g/m{sup 3}, respectively. The ranges of mean PM10 and PM2.5 in-vehicle levels in Sacramento were 20--40 {micro}g/m{sup 3} and 6--22 {micro}g/m{sup 3}, respectively. In general, pollutant levels inside or just outside the vehicles were higher than those measured at the roadside stations or the ambient air stations. In-vehicle pollutant levels were consistently higher in Los Angeles than Sacramento. Pollutant levels measured inside vehicles traveling in a carpool lane were much lower than those in the right-hand, slower lanes. Under the study conditions, factors such as vehicle type and ventilation and little effect on in-vehicle pollutant levels. Other factors, such as roadway type, freeway congestion level, and time-of-day had some influence on in-vehicle pollution levels.« less

Influence of nitromethane concentration on ignition energy and explosion parameters in gaseous nitromethane/air mixtures.

PubMed

Zhang, Qi; Li, Wei; Lin, Da-Chao; He, Ning; Duan, Yun

2011-01-30

The aim of this paper is to provide new experimental data of the minimum ignition energy (MIE) of gaseous nitromethane/air mixtures to discuss the explosion pressure and the flame temperature as a function of nitromethane concentration. Observations on the influence of nitromethane concentration on combustion pressure and temperature through the pressure and temperature measure system show that peak temperature (the peak of combustion temperature wave) is always behind peak pressure (the peak of the combustion pressure wave) in arrival time, the peak combustion pressure of nitromethane increases in the range of its volume fraction 10-40% as the concentration of nitromethane increases, and it slightly decreases in the range of 40-50%. The maximum peak pressure is equal to 0.94 MPa and the minimum peak pressure 0.58 MPa. Somewhat similar to the peak pressure, the peak combustion temperature increases with the volume fraction of nitromethane in the range of 10-40%, and slightly decreases in 40-50%. The maximum peak temperature is 1340 °C and the minimum 860 °C. The combustion temperature rise rate increases with the concentration of nitromethane in 10-30%, while decreases in 30-50% and its maximum value of combustion temperature rise rate in 10-50% is 4200 °C/s at the volume fraction of 30%. Influence of the concentration of nitromethane on the combustion pressure rise rate is relatively complicated, and the maximum value of rise rate of combustion pressure wave in 10-50% is 11 MPa/s at the concentration 20%. Copyright © 2010 Elsevier B.V. All rights reserved.

Exploring the potential relationship between indoor air quality and the concentration of airborne culturable fungi: a combined experimental and neural network modeling study.

PubMed

Liu, Zhijian; Cheng, Kewei; Li, Hao; Cao, Guoqing; Wu, Di; Shi, Yunjie

2018-02-01

Indoor airborne culturable fungi exposure has been closely linked to occupants' health. However, conventional measurement of indoor airborne fungal concentration is complicated and usually requires around one week for fungi incubation in laboratory. To provide an ultra-fast solution, here, for the first time, a knowledge-based machine learning model is developed with the inputs of indoor air quality data for estimating the concentration of indoor airborne culturable fungi. To construct a database for statistical analysis and model training, 249 data groups of air quality indicators (concentration of indoor airborne culturable fungi, indoor/outdoor PM 2.5 and PM 10 concentrations, indoor temperature, indoor relative humidity, and indoor CO 2 concentration) were measured from 85 residential buildings of Baoding (China) during the period of 2016.11.15-2017.03.15. Our results show that artificial neural network (ANN) with one hidden layer has good prediction performances, compared to a support vector machine (SVM). With the tolerance of ± 30%, the prediction accuracy of the ANN model with ten hidden nodes can at highest reach 83.33% in the testing set. Most importantly, we here provide a quick method for estimating the concentration of indoor airborne fungi that can be applied to real-time evaluation.

Strength of smoke-free air laws and indoor air quality.

PubMed

Lee, Kiyoung; Hahn, Ellen J; Robertson, Heather E; Lee, Seongjik; Vogel, Suzann L; Travers, Mark J

2009-04-01

Smoke-free air laws have been implemented in many Kentucky communities to protect the public from the harmful effects of secondhand smoke exposure. The impact of different strengths of smoke-free air laws on indoor air quality was assessed. Indoor air quality in hospitality venues was assessed in seven communities before and after comprehensive smoke-free air laws and in two communities only after partial smoke-free air laws. One community was measured three times: before any smoke-free air law, after the initial partial law, and after the law was strengthened to cover all workplaces and public places with few exemptions. Real-time measurements of particulate matters with 2.5 mum aerodynamic diameter or smaller (PM(2.5)) were obtained. When comprehensive smoke-free air laws were implemented, indoor PM(2.5) concentrations decreased significantly from 161 to 20 microg/m3. In one community that implemented a comprehensive smoke-free law after initially passing a partial law, indoor PM(2.5) concentrations were 304 microg/m3 before the law, 338 microg/m3 after the partial law, and 9 microg/m3 after the comprehensive law. The study clearly demonstrated that partial smoke-free air laws do not improve indoor air quality. A significant linear trend indicated that PM(2.5) levels in the establishments decreased with fewer numbers of burning cigarettes. Only comprehensive smoke-free air laws are effective in reducing indoor air pollution from secondhand tobacco smoke.

Changes in Air CO₂ Concentration Differentially Alter Transcript Levels of NtAQP1 and NtPIP2;1 Aquaporin Genes in Tobacco Leaves.

PubMed

Secchi, Francesca; Schubert, Andrea; Lovisolo, Claudio

2016-04-14

The aquaporin specific control on water versus carbon pathways in leaves is pivotal in controlling gas exchange and leaf hydraulics. We investigated whether Nicotiana tabacum aquaporin 1 (NtAQP1) and Nicotiana tabacum plasma membrane intrinsic protein 2;1 (NtPIP2;1) gene expression varies in tobacco leaves subjected to treatments with different CO₂ concentrations (ranging from 0 to 800 ppm), inducing changes in photosynthesis, stomatal regulation and water evaporation from the leaf. Changes in air CO₂ concentration ([CO₂]) affected net photosynthesis (Pn) and leaf substomatal [CO₂] (Ci). Pn was slightly negative at 0 ppm air CO₂; it was one-third that of ambient controls at 200 ppm, and not different from controls at 800 ppm. Leaves fed with 800 ppm [CO₂] showed one-third reduced stomatal conductance (gs) and transpiration (E), and their gs was in turn slightly lower than in 200 ppm- and in 0 ppm-treated leaves. The 800 ppm air [CO₂] strongly impaired both NtAQP1 and NtPIP2;1 gene expression, whereas 0 ppm air [CO₂], a concentration below any in vivo possible conditions and specifically chosen to maximize the gene expression alteration, increased only the NtAQP1 transcript level. We propose that NtAQP1 expression, an aquaporin devoted to CO₂ transport, positively responds to CO₂ scarcity in the air in the whole range 0-800 ppm. On the contrary, expression of NtPIP2;1, an aquaporin not devoted to CO₂ transport, is related to water balance in the leaf, and changes in parallel with gs. These observations fit in a model where upregulation of leaf aquaporins is activated at low Ci, while downregulation occurs when high Ci saturates photosynthesis and causes stomatal closure.

Mold contamination of automobile air conditioner systems.

PubMed

Kumar, P; Lopez, M; Fan, W; Cambre, K; Elston, R C

1990-02-01

Eight cars belonging to patients who were found to have exacerbation of allergic rhinitis and bronchial asthma after turning on the air conditioner in their cars were examined. Mold concentrations inside the passenger compartment with the a/c turned off and at different climate control settings were lower than concentrations in the outside air. After turning on the air conditioner to "Max", cultures obtained at various intervals revealed that mold concentrations decreased significantly with time. Furthermore, placement of a filter at the portal of entry of outside air significantly reduced the mold concentration in the passenger compartment.

Radon in indoor concentrations and indoor concentrations of metal dust particles in museums and other public buildings.

PubMed

Carneiro, G L; Braz, D; de Jesus, E F; Santos, S M; Cardoso, K; Hecht, A A; Dias da Cunha, Moore K

2013-06-01

The aim of this study was to evaluate the public and occupational exposure to radon and metal-bearing particles in museums and public buildings located in the city of Rio de Janeiro, Brazil. For this study, four buildings were selected: two historic buildings, which currently house an art gallery and an art museum; and two modern buildings, a chapel and a club. Integrated radon concentration measurements were performed using passive radon detectors with solid state nuclear track detector-type Lexan used as nuclear track detector. Air samplers with a cyclone were used to collect the airborne particle samples that were analyzed by the particle-induced X-ray emission technique. The average unattached-radon concentrations in indoor air in the buildings were above 40 Bq/m(3), with the exception of Building D as measured in 2009. The average radon concentrations in indoor air in the four buildings in 2009 were below the recommended reference level by World Health Organization (100 Bq/m(3)); however, in 2011, the average concentrations of radon in Buildings A and C were above this level, though lower than 300 Bq/m(3). The average concentrations of unattached radon were lower than 148 Bq/m(3) (4pCi/L), the USEPA level recommended to take action to reduce the concentrations of radon in indoor air. The unattached-radon average concentrations were also lower than the value recommended by the European Union for new houses. As the unattached-radon concentrations were below the international level recommended to take action to reduce the radon concentration in air, it was concluded that during the period of sampling, there was low risk to human health due to the inhalation of unattached radon in these four buildings.

A sensitive method using SPME pre-concentration for the quantification of aromatic amines in indoor air.

PubMed

Lucaire, Vincent; Schwartz, Jean-Jacques; Delhomme, Olivier; Ocampo-Torres, Ruben; Millet, Maurice

2018-03-01

Monitoring the levels of aliphatic and aromatic amines (AA) in indoor air is important to protect human health because of exposure to these compounds through diet and inhalation. A sampling and analytical method using XAD-2 cartridges and gas chromatography coupled to mass spectrometry used for assessing 25 AA in different smoking and non-smoking indoor environment was developed. After sampling and delivering 1 m 3 of air (6-8 h sampling), an adsorbent was ultrasonically extracted with acetonitrile, concentrated to 1 mL and diluted in 25 mL of water (pH = 9; 5% NaCl), and then extracted for 40 min at 80 °C using a divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber and injected in a GC/MS system. With this method, 22 of the 25 AA can be analyzed with detection limits up to five times lower than that of classic liquid injection. Benzylamine, 3-aminophenol, and 4-aminophenol were not detected with the solid-phase micro-extraction (SPME) method. It can be assumed that aminophenols required a derivatization step for their analysis by GC as these molecules were not detected regardless of the injection mode used. Graphical abstract Analysis of aromatic amines in indoor air by SPME-GC/MS.

Biofiltration of air contaminated by styrene: Effect of nitrogen supply, gas flow rate, and inlet concentration

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

Jorio, H.; Bibeau, L.; Heitz, M.

2000-05-01

The biofiltration process is a promising technology for the treatment of dilute styrene emissions in air. The efficiency of this process is however strongly dependent upon various operational parameters such as the filter bed characteristics, nutrient supplies, input contaminant concentrations, and gas flow rates. The biofiltration of air containing styrene vapors was therefore investigated, employing a novel biomass filter material, in two identical but separate laboratory scale biofiltration units (units 1 and 2), both biofilters being initially inoculated with a microbial consortium. Each biofilter was irrigated with a nutrient solution supplying nitrogen in one of two forms; i.e., mainly asmore » ammonia for unit 1 and exclusively as nitrate for unit 2. The experimental results have revealed that greater styrene elimination rates are achieved in the biofilter supplied with ammonia as the major nitrogen source in comparison to the lesser elimination performance obtained with the nitrate provided biofilter. However, in achieving the high styrene removal rates in the ammonia supplied biofilter, the excess of biomass accumulates on the filtering pellets and causes progressive clogging of the filter media. Furthermore, the effectiveness of nitrate supply as the sole nitrogen nutrient form, on reducing or controlling the biomass accumulation in the filter media in comparison to ammonia, could not be satisfactorily demonstrated because the two biofilters operated with very different styrene elimination capacities. The monitoring of the carbon dioxide concentration profile through both biofilters revealed that the ratio of carbon dioxide produced to the styrene removed was approximately 3/1, which confirms the complete biodegradation of removed styrene, given that some of the organic carbon consumed is also used for the microbial growth. The effects of the most important design parameters, namely styrene input concentrations and gas flow rates, were investigated for

Neighbourhood Characteristics and Long-Term Air Pollution Levels Modify the Association between the Short-Term Nitrogen Dioxide Concentrations and All-Cause Mortality in Paris

PubMed Central

Deguen, Séverine; Petit, Claire; Delbarre, Angélique; Kihal, Wahida; Padilla, Cindy; Benmarhnia, Tarik; Lapostolle, Annabelle; Chauvin, Pierre; Zmirou-Navier, Denis

2015-01-01

Background While a great number of papers have been published on the short-term effects of air pollution on mortality, few have tried to assess whether this association varies according to the neighbourhood socioeconomic level and long-term ambient air concentrations measured at the place of residence. We explored the effect modification of 1) socioeconomic status, 2) long-term NO2 ambient air concentrations, and 3) both combined, on the association between short-term exposure to NO2 and all-cause mortality in Paris (France). Methods A time-stratified case-crossover analysis was performed to evaluate the effect of short-term NO2 variations on mortality, based on 79,107 deaths having occurred among subjects aged over 35 years, from 2004 to 2009, in the city of Paris. Simple and double interactions were statistically tested in order to analyse effect modification by neighbourhood characteristics on the association between mortality and short-term NO2 exposure. The data was estimated at the census block scale (n=866). Results The mean of the NO2 concentrations during the five days prior to deaths were associated with an increased risk of all-cause mortality: overall Excess Risk (ER) was 0.94% (95%CI=[0.08;1.80]. A higher risk was revealed for subjects living in the most deprived census blocks in comparison with higher socioeconomic level areas (ER=3.14% (95%CI=[1.41-4.90], p<0.001). Among these deprived census blocks, excess risk was even higher where long-term average NO2 concentrations were above 55.8 μg/m3 (the top tercile of distribution): ER=4.84% (95%CI=[1.56;8.24], p for interaction=0.02). Conclusion Our results show that people living in census blocks characterized by low socioeconomic status are more vulnerable to air pollution episodes. There is also an indication that people living in these disadvantaged census blocks might experience even higher risk following short-term air pollution episodes, when they are also chronically exposed to higher NO2 levels

Neighbourhood Characteristics and Long-Term Air Pollution Levels Modify the Association between the Short-Term Nitrogen Dioxide Concentrations and All-Cause Mortality in Paris.

PubMed

Deguen, Séverine; Petit, Claire; Delbarre, Angélique; Kihal, Wahida; Padilla, Cindy; Benmarhnia, Tarik; Lapostolle, Annabelle; Chauvin, Pierre; Zmirou-Navier, Denis

2015-01-01

While a great number of papers have been published on the short-term effects of air pollution on mortality, few have tried to assess whether this association varies according to the neighbourhood socioeconomic level and long-term ambient air concentrations measured at the place of residence. We explored the effect modification of 1) socioeconomic status, 2) long-term NO2 ambient air concentrations, and 3) both combined, on the association between short-term exposure to NO2 and all-cause mortality in Paris (France). A time-stratified case-crossover analysis was performed to evaluate the effect of short-term NO2 variations on mortality, based on 79,107 deaths having occurred among subjects aged over 35 years, from 2004 to 2009, in the city of Paris. Simple and double interactions were statistically tested in order to analyse effect modification by neighbourhood characteristics on the association between mortality and short-term NO2 exposure. The data was estimated at the census block scale (n=866). The mean of the NO2 concentrations during the five days prior to deaths were associated with an increased risk of all-cause mortality: overall Excess Risk (ER) was 0.94% (95%CI=[0.08;1.80]. A higher risk was revealed for subjects living in the most deprived census blocks in comparison with higher socioeconomic level areas (ER=3.14% (95%CI=[1.41-4.90], p<0.001). Among these deprived census blocks, excess risk was even higher where long-term average NO2 concentrations were above 55.8 μg/m3 (the top tercile of distribution): ER=4.84% (95%CI=[1.56;8.24], p for interaction=0.02). Our results show that people living in census blocks characterized by low socioeconomic status are more vulnerable to air pollution episodes. There is also an indication that people living in these disadvantaged census blocks might experience even higher risk following short-term air pollution episodes, when they are also chronically exposed to higher NO2 levels.

Effects of breathing pattern and inspired air conditions on breath condensate volume, pH, nitrite, and protein concentrations.

PubMed

McCafferty, J B; Bradshaw, T A; Tate, S; Greening, A P; Innes, J A

2004-08-01

The effects of breathing pattern and inspired air conditions on the volume and content of exhaled breath condensate (EBC) were investigated. Total exhaled water (TEW), EBC volume, pH, nitrite and protein concentrations were measured in three groups of 10 healthy subjects breathing into a condenser at different target minute ventilations (Vm), tidal volumes (Vt), and inspired air conditions. The volumes of both TEW and EBC increased significantly with Vm. For Vm 7.5, 15 and 22.5 l/min, mean (SD) EBC was 627 (258) microl, 1019 (313) microl, and 1358 (364) microl, respectively (p<0.001) and TEW was 1879 (378) microl, 2986 (496) microl, and 4679 (700) microl, respectively (p<0.001). TEW was significantly higher than EBC, reflecting a condenser efficiency of 40% at a target Vm of 7.5 l/min which reduced to 29% at Vm 22.5 l/min. Lower Vt gave less TEW than higher Vt (26.6 v 30.7 microl/l, mean difference 4.1 (95% CI 2.6 to 5.6), p<0.001) and a smaller EBC volume (4.3 v 7.6 microl/l, mean difference 3.4 (95% CI 2.3 to 4.5), p<0.001). Cooler and drier inspired air yielded less water vapour and less breath condensate than standard conditions (p<0.05). Changes in the breathing pattern had no effect on EBC protein and nitrite concentrations and pH. These results show that condensate volume can be increased by using high Vt and increased Vm without compromising the dilution of the sample.

Secondhand smoke exposure and risk following the Irish smoking ban: an assessment of salivary cotinine concentrations in hotel workers and air nicotine levels in bars

PubMed Central

Mulcahy, M; Evans, D; Hammond, S; Repace, J; Byrne, M

2005-01-01

Objective: To investigate whether the Irish smoking ban has had an impact on secondhand smoke (SHS) exposures for hospitality workers. Design, setting, and participants: Before and after the smoking ban a cohort of workers (n = 35) from a sample of city hotels (n = 15) were tested for saliva cotinine concentrations and completed questionnaires. Additionally, a random sample (n = 20) of city centre bars stratified by size (range 400–5000 square feet), were tested for air nicotine concentrations using passive samplers before and after the ban. Main outcome measures: Salivary cotinine concentrations (ng/ml), duration of self reported exposures to secondhand smoke, air nicotine (µg/cubic metre). Results: Cotinine concentrations reduced by 69%, from 1.6 ng/ml to 0.5 ng/ml median (SD 1.29; p < 0.005). Overall 74% of subjects experienced decreases (range 16–99%), with 60% showing a halving of exposure levels at follow up. Self reported exposure to SHS at work showed a significant reduction from a median 30 hours a week to zero (p < 0.001). There was an 83% reduction in air nicotine concentrations from median 35.5 µg/m3 to 5.95 µg/m3 (p < 0.001). At baseline, three bars (16%) were below the 6.8 µg/m3 air nicotine significant risk level for lung cancer alone; at follow up this increased to 10 (53%). Conclusions: Passive smoking and associated risks were significantly reduced but not totally eliminated. Exposure to SHS is still possible for those working where smoking is still allowed and those working where smoke may migrate from outdoor areas. Further research is required to assess the true extent and magnitude of these exposures. PMID:16319361

Statistics of concentrations due to single air pollution sources to be applied in numerical modelling of pollutant dispersion

NASA Astrophysics Data System (ADS)

Tumanov, Sergiu

A test of goodness of fit based on rank statistics was applied to prove the applicability of the Eggenberger-Polya discrete probability law to hourly SO 2-concentrations measured in the vicinity of single sources. With this end in view, the pollutant concentration was considered an integral quantity which may be accepted if one properly chooses the unit of measurement (in this case μg m -3) and if account is taken of the limited accuracy of measurements. The results of the test being satisfactory, even in the range of upper quantiles, the Eggenberger-Polya law was used in association with numerical modelling to estimate statistical parameters, e.g. quantiles, cumulative probabilities of threshold concentrations to be exceeded, and so on, in the grid points of a network covering the area of interest. This only needs accurate estimations of means and variances of the concentration series which can readily be obtained through routine air pollution dispersion modelling.

Protein and starch concentrates of air-classified field pea and zero-tannin faba bean for weaned pigs.

PubMed

Gunawardena, C K; Zijlstra, R T; Goonewardene, L A; Beltranena, E

2010-08-01

Air-classified pulse (non-oilseed legume) protein and starch may replace specialty protein and starch feedstuffs in diets for weaned pigs. In Exp. 1, three specialty protein sources (5% soy protein concentrate, 5% corn gluten meal, and 5% menhaden meal in the control diet) were replaced with 16% zero-tannin hulled or dehulled faba bean, or 17.5% field pea protein concentrate. In total, 192 group-housed pigs (2 gilts and 2 barrows per pen; BW = 7.5 +/- 1.4 kg) were fed wheat-based diets (3.60 Mcal/kg of DE and 3.3 g of standardized ileal digestible Lys/Mcal DE) over 28 d for 12 pen observations per each of 4 diets. Overall, protein source did not affect ADFI, ADG, or G:F. Apparent total tract digestibility (ATTD) of DM, GE, and P was greater (P < 0.05) for dehulled faba bean and field pea protein concentrate diets than the diet with 3 specialty protein sources. In Exp. 2, faba bean and field pea starch concentrates were compared with corn, wheat, tapioca, and potato starch as dietary energy sources. In total, 36 individually housed barrows (BW = 8.0 +/- 1.5 kg) were fed 1 of 6 diets for 15 d. Feces and urine were collected from d 8 to 14, and jugular blood was sampled after overnight fast and refeeding on d 15. Starch source did not affect N retention as a percentage of N intake. For d 0 to 14, ADFI of pigs fed field pea starch was greater (P < 0.05) than pigs fed corn, wheat, potato, and faba bean starch. Pigs fed tapioca, field pea, wheat, or corn starch grew faster (P < 0.05) than those fed faba bean or potato starch. For d 0 to 14, pigs fed corn or wheat starch had a 0.1 greater (P < 0.05) G:F than pigs fed faba bean, field pea, or potato starch. The ATTD of DM, GE, CP, and starch and the DE value of potato starch were much less (P < 0.05) than those of other starch diets. Postprandial plasma glucose was 4.9, 6.3, and 9 mmol/L greater (P < 0.05) for pigs fed tapioca than for pigs fed faba bean, wheat, and potato starch, respectively. However, postprandial plasma

Impact of the formaldehyde concentration in the air on the sink effect of a coating material

NASA Astrophysics Data System (ADS)

Tiffonnet, Anne-Lise; Tourreilles, Céline; Duforestel, Thierry

2018-02-01

This study aims to characterize, from a numerical modelling, the sorption behaviour of a material (a plasticised flooring material) when it is exposed to a pollutant commonly encountered in indoor environments (formaldehyde). It deals with the influence of the pollutant concentration in the room air on the sink effect of the material. The numerical simulations are based on a macroscopic modelling using experimental test results obtained elsewhere. The consequences on the room inertia are also discussed, and analogies between mass transfer and heat transfer are highlighted.

Final Technical Report - SciDAC Cooperative Agreement: Center for Wave Interactions with Magnetohydrodynamics

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

Schnack, Dalton D.

Final technical report for research performed by Dr. Thomas G. Jenkins in collaboration with Professor Dalton D. Schnack on SciDAC Cooperative Agreement: Center for Wave Interactions with Magnetohydrodyanics, DE-FC02-06ER54899, for the period of 8/15/06 - 8/14/11. This report centers on the Slow MHD physics campaign work performed by Dr. Jenkins while at UW-Madison and then at Tech-X Corporation. To make progress on the problem of RF induced currents affect magnetic island evolution in toroidal plasmas, a set of research approaches are outlined. Three approaches can be addressed in parallel. These are: (1) Analytically prescribed additional term in Ohm's law tomore » model the effect of localized ECCD current drive; (2) Introduce an additional evolution equation for the Ohm's law source term. Establish a RF source 'box' where information from the RF code couples to the fluid evolution; and (3) Carry out a more rigorous analytic calculation treating the additional RF terms in a closure problem. These approaches rely on the necessity of reinvigorating the computation modeling efforts of resistive and neoclassical tearing modes with present day versions of the numerical tools. For the RF community, the relevant action item is - RF ray tracing codes need to be modified so that general three-dimensional spatial information can be obtained. Further, interface efforts between the two codes require work as well as an assessment as to the numerical stability properties of the procedures to be used.« less

Influence of the meteorological parameters on CFCs and SF6 concentration in the air of Krakow, Poland

NASA Astrophysics Data System (ADS)

Bielewski, Jarosław; Najman, Joanna; Śliwka, Ireneusz; Bartyzel, Jakub; Rosiek, Janusz

2013-04-01

key words: gas chromatography, trace gases, CFCs and SF6 measurements in urban area. Halogenated compounds (chlorofluorocarbons-CFCs), both natural and industrial, so-called freons, currently exist as trace gases in the entire human environment. The CFCs cause ozone depletion in the stratosphere. Moreover CFCs and SF6 take part in intensification of the greenhouse effect. The decisions of the Vienna Convention (1985) and of the Montreal Protocol (1987) limited the world production level of CFCs in the year 1989 at least 35% after 2004, 90% after 2015 and total reduction after year 2030. On account of international agreements, the measurements of CFCs and SF6 in air were started. Measurement "clean" stations were situated at places outside of urban areas influence and gathered on world program - AGAGE (Advanced Global Atmospheric Gases Experiment). One of these stations is Mace Head (Ireland, 53o N, 10o W), which participates in AGAGE since 1987 [1] and in European InGOS (Integrated non-CO2 Greenhouse gas Observing System) program since 2011. Similar research is also conducted in Central Europe, in urban area of Krakow (Poland, 50o N, 19o E) since 1997. The work discusses results from 15 years of concentration measurements (in the years 1997-2012) of selected halocarbons and SF6 in Krakow. To obtain concentrations of measured compounds the mathematical procedure has been used, where concentrations were calculated using a five points Lagrange's interpolation method. Using temporary measurement data were determined daily arithmetic means and their standard deviations. Based on these data, efficiency of Montreal Protocol legislation, implemented in Poland (The Journal of Laws No. 52) could be assessed [2]. Additionally cut-off filtration method was used to estimate trend of the base line of individual air pollutant. Rejected exceedances of base lines were corelated with meteorological characteristics of Krakow region to evaluate possible sources of pollution. The

Air-breathing behavior, oxygen concentrations, and ROS defense in the swimbladders of two erythrinid fish, the facultative air-breathing jeju, and the non-air-breathing traira during normoxia, hypoxia and hyperoxia.

PubMed

Pelster, Bernd; Wood, Chris M; Jung, Ellen; Val, Adalberto L

2018-05-01

The jeju Hoplerythrinus unitaeniatus and the traira Hoplias malabaricus are two neighboring genera from the family of erythrinid fish, both possessing a two-chambered physostomous swimbladder. In the jeju the anterior section of the posterior bladder is highly vascularized, and the swimbladder is used for aerial respiration; the traira, in turn, is a water-breather that uses the swimbladder as a buoyancy organ and not for aerial oxygen uptake. Measurement of swimbladder oxygen partial pressure (PO 2 ) of fish kept at 26 °C in normoxic, hyperoxic (28-32 mg O 2 L - 1 ) or hypoxic (1-1.5 mg O 2 L - 1 ) water revealed constant values in traira swimbladder. Under normoxic conditions in the jeju swimbladder PO 2 was higher than in traira, and the PO 2 significantly increased under hyperoxic conditions, even in the absence of air breathing. In jeju, air-breathing activity increased significantly under hypoxic conditions. Hypoxic air-breathing activity was negatively correlated to swimbladder PO 2 , indicating that the swimbladder was intensely used for gas exchange under these conditions. In traira, the capacity of the ROS defense system, as assessed by measurement of activities of enzymes involved in ROS degradation and total glutathione (GSH + GSSG) concentration, was elevated after 4 h of hyperoxic and/or hypoxic exposure, although swimbladder PO 2 was not affected. In jeju, experiencing a higher variability in swimbladder PO 2 due to the air-breathing activity, only a reduced responsiveness of the ROS defense system to changing environmental PO 2 was detected.

Developmental exposure to concentrated ambient ultrafine particulate matter air pollution in mice results in persistent and sex-dependent behavioral neurotoxicity and glial activation.

PubMed

Allen, Joshua L; Liu, Xiufang; Weston, Douglas; Prince, Lisa; Oberdörster, Günter; Finkelstein, Jacob N; Johnston, Carl J; Cory-Slechta, Deborah A

2014-07-01

The brain appears to be a target of air pollution. This study aimed to further ascertain behavioral and neurobiological mechanisms of our previously observed preference for immediate reward (Allen, J. L., Conrad, K., Oberdorster, G., Johnston, C. J., Sleezer, B., and Cory-Slechta, D. A. (2013). Developmental exposure to concentrated ambient particles and preference for immediate reward in mice. Environ. Health Perspect. 121, 32-38), a phenotype consistent with impulsivity, in mice developmentally exposed to inhaled ultrafine particles. It examined the impact of postnatal and/or adult concentrated ambient ultrafine particles (CAPS) or filtered air on another behavior thought to reflect impulsivity, Fixed interval (FI) schedule-controlled performance, and extended the assessment to learning/memory (novel object recognition (NOR)), and locomotor activity to assist in understanding behavioral mechanisms of action. In addition, levels of brain monoamines and amino acids, and markers of glial presence and activation (GFAP, IBA-1) were assessed in mesocorticolimbic brain regions mediating these cognitive functions. This design produced four treatment groups/sex of postnatal/adult exposure: Air/Air, Air/CAPS, CAPS/Air, and CAPS/CAPS. FI performance was adversely influenced by CAPS/Air in males, but by Air/CAPS in females, effects that appeared to reflect corresponding changes in brain mesocorticolimbic dopamine/glutamate systems that mediate FI performance. Both sexes showed impaired short-term memory on the NOR. Mechanistically, cortical and hippocampal changes in amino acids raised the potential for excitotoxicity, and persistent glial activation was seen in frontal cortex and corpus callosum of both sexes. Collectively, neurodevelopment and/or adulthood CAPS can produce enduring and sex-dependent neurotoxicity. Although mechanisms of these effects remain to be fully elucidated, findings suggest that neurodevelopment and/or adulthood air pollution exposure may represent

Trends of NOx, NO2 and O3 concentrations at three different types of air quality monitoring stations in Athens, Greece

NASA Astrophysics Data System (ADS)

Mavroidis, I.; Ilia, M.

2012-12-01

This work presents a systematic analysis and evaluation of the historic and current levels of atmospheric pollution in the Athens metropolitan region, regarding nitrogen oxides (NOx = NO + NO2), ozone (O3) and the NO2/NOx and NO/NO2 concentration ratios. Hourly, daily, monthly, seasonal and annual pollutant variations are examined and compared, using the results of concentration time series from three different stations of the national network for air pollution monitoring, one urban-traffic, one urban-background and one suburban-background. Concentration data are also related to meteorological parameters. The results show that the traffic affected station of Patission Street presents the higher NOx values and the lower concentrations of O3, while it is the station with the highest number of NO2 limit exceedances. The monitoring data suggest, inter alia, that there is a change in the behaviour of the suburban-background station of Liossia at about year 2000, indicating that the exact location of this station may need to be reconsidered. Comparison of NOx concentrations in Athens with concentrations in urban areas of other countries reveal that the Patission urban-traffic station records very high NOx concentrations, while remarkably high is the ratio of NO2 concentrations recorded at the urban-traffic vs. the urban-background station in Athens, indicating the overarching role of vehicles and traffic congestion on NO2 formation. The NO2/NOx ratio in the urban-traffic station appears to be almost constant with time, while it has been increasing in other urban areas, such as London and Seoul, suggesting an increased effect of primary NO2 in these areas. Diesel passenger cars were only recently allowed in Athens and, therefore, NO2 trends should be carefully monitored since a possible increase in primary NO2 may affect compliance with NO2 air quality standards.

Impacts of Hazardous Air Pollutants Emitted from Phosphate Fertilizer Production Plants on their Ambient Concentration Levels in the Tampa Bay Area

EPA Science Inventory

The concentrations and distribution of Hazardous Air Pollutants (HAPs) metals emitted from four phosphate fertilizer plants in Central Florida, as well as their environmental and health impacts, were assessed. The dominant HAP metals emitted from the stacks of these plants were M...

Assessment of air quality benefits from national air pollution control policies in China. Part II: Evaluation of air quality predictions and air quality benefits assessment

NASA Astrophysics Data System (ADS)

Wang, Litao; Jang, Carey; Zhang, Yang; Wang, Kai; Zhang, Qiang; Streets, David; Fu, Joshua; Lei, Yu; Schreifels, Jeremy; He, Kebin; Hao, Jiming; Lam, Yun-Fat; Lin, Jerry; Meskhidze, Nicholas; Voorhees, Scott; Evarts, Dale; Phillips, Sharon

2010-09-01

Following the meteorological evaluation in Part I, this Part II paper presents the statistical evaluation of air quality predictions by the U.S. Environmental Protection Agency (U.S. EPA)'s Community Multi-Scale Air Quality (Models-3/CMAQ) model for the four simulated months in the base year 2005. The surface predictions were evaluated using the Air Pollution Index (API) data published by the China Ministry of Environmental Protection (MEP) for 31 capital cities and daily fine particulate matter (PM 2.5, particles with aerodiameter less than or equal to 2.5 μm) observations of an individual site in Tsinghua University (THU). To overcome the shortage in surface observations, satellite data are used to assess the column predictions including tropospheric nitrogen dioxide (NO 2) column abundance and aerosol optical depth (AOD). The result shows that CMAQ gives reasonably good predictions for the air quality. The air quality improvement that would result from the targeted sulfur dioxide (SO 2) and nitrogen oxides (NO x) emission controls in China were assessed for the objective year 2010. The results show that the emission controls can lead to significant air quality benefits. SO 2 concentrations in highly polluted areas of East China in 2010 are estimated to be decreased by 30-60% compared to the levels in the 2010 Business-As-Usual (BAU) case. The annual PM 2.5 can also decline by 3-15 μg m -3 (4-25%) due to the lower SO 2 and sulfate concentrations. If similar controls are implemented for NO x emissions, NO x concentrations are estimated to decrease by 30-60% as compared with the 2010 BAU scenario. The annual mean PM 2.5 concentrations will also decline by 2-14 μg m -3 (3-12%). In addition, the number of ozone (O 3) non-attainment areas in the northern China is projected to be much lower, with the maximum 1-h average O 3 concentrations in the summer reduced by 8-30 ppb.

Strength of smoke-free air laws and indoor air quality

PubMed Central

Hahn, Ellen J.; Robertson, Heather E.; Vogel, Suzann L.; Travers, Mark J.

2009-01-01

Introduction: Smoke-free air laws have been implemented in many Kentucky communities to protect the public from the harmful effects of secondhand smoke exposure. The impact of different strengths of smoke-free air laws on indoor air quality was assessed. Methods: Indoor air quality in hospitality venues was assessed in seven communities before and after comprehensive smoke-free air laws and in two communities only after partial smoke-free air laws. One community was measured three times: before any smoke-free air law, after the initial partial law, and after the law was strengthened to cover all workplaces and public places with few exemptions. Real-time measurements of particulate matters with 2.5 μm aerodynamic diameter or smaller (PM2.5) were obtained. Results: When comprehensive smoke-free air laws were implemented, indoor PM2.5 concentrations decreased significantly from 161 to 20 μg/m3. In one community that implemented a comprehensive smoke-free law after initially passing a partial law, indoor PM2.5 concentrations were 304 μg/m3 before the law, 338 μg/m3 after the partial law, and 9 μg/m3 after the comprehensive law. Discussion: The study clearly demonstrated that partial smoke-free air laws do not improve indoor air quality. A significant linear trend indicated that PM2.5 levels in the establishments decreased with fewer numbers of burning cigarettes. Only comprehensive smoke-free air laws are effective in reducing indoor air pollution from secondhand tobacco smoke. PMID:19346510

Predictability Analysis of PM10 Concentrations in Budapest

NASA Astrophysics Data System (ADS)

Ferenczi, Zita

2013-04-01

Climate, weather and air quality may have harmful effects on human health and environment. Over the past few hundred years we had to face the changes in climate in parallel with the changes in air quality. These observed changes in climate, weather and air quality continuously interact with each other: pollutants are changing the climate, thus changing the weather, but climate also has impacts on air quality. The increasing number of extreme weather situations may be a result of climate change, which could create favourable conditions for rising of pollutant concentrations. Air quality in Budapest is determined by domestic and traffic emissions combined with the meteorological conditions. In some cases, the effect of long-range transport could also be essential. While the time variability of the industrial and traffic emissions is not significant, the domestic emissions increase in winter season. In recent years, PM10 episodes have caused the most critical air quality problems in Budapest, especially in winter. In Budapest, an air quality network of 11 stations detects the concentration values of different pollutants hourly. The Hungarian Meteorological Service has developed an air quality prediction model system for the area of Budapest. The system forecasts the concentration of air pollutants (PM10, NO2, SO2 and O3) for two days in advance. In this work we used meteorological parameters and PM10 data detected by the stations of the air quality network, as well as the forecasted PM10 values of the air quality prediction model system. In this work we present the evaluation of PM10 predictions in the last two years and the most important meteorological parameters affecting PM10 concentration. The results of this analysis determine the effect of the meteorological parameters and the emission of aerosol particles on the PM10 concentration values as well as the limits of this prediction system.

Novel approach for tomographic reconstruction of gas concentration distributions in air: Use of smooth basis functions and simulated annealing

NASA Astrophysics Data System (ADS)

Drescher, A. C.; Gadgil, A. J.; Price, P. N.; Nazaroff, W. W.

Optical remote sensing and iterative computed tomography (CT) can be applied to measure the spatial distribution of gaseous pollutant concentrations. We conducted chamber experiments to test this combination of techniques using an open path Fourier transform infrared spectrometer (OP-FTIR) and a standard algebraic reconstruction technique (ART). Although ART converged to solutions that showed excellent agreement with the measured ray-integral concentrations, the solutions were inconsistent with simultaneously gathered point-sample concentration measurements. A new CT method was developed that combines (1) the superposition of bivariate Gaussians to represent the concentration distribution and (2) a simulated annealing minimization routine to find the parameters of the Gaussian basis functions that result in the best fit to the ray-integral concentration data. This method, named smooth basis function minimization (SBFM), generated reconstructions that agreed well, both qualitatively and quantitatively, with the concentration profiles generated from point sampling. We present an analysis of two sets of experimental data that compares the performance of ART and SBFM. We conclude that SBFM is a superior CT reconstruction method for practical indoor and outdoor air monitoring applications.

Short-term effects of air temperature on plasma metabolite concentrations in patients undergoing cardiac catheterization

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

Hampel, Regina, E-mail: regina.hampel@helmholtz-mu

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 metabolites related to cardiovascular disease. Methods: Concentrations of 45 acylcarnitines, 15 amino acids, ketone bodies and total free fatty acids were available in 2869 participants from the CATHeterization GENetics cohort recruited at the Duke University Cardiac Catheterization Clinic (Durham, NC) between 2001 and 2007. Ten metabolites were selected based on quality criteria and cluster analysis. Daily averages of meteorological variables were obtained from the North American Regionalmore » Reanalysis project. Immediate, lagged, and cumulative temperature effects on metabolite concentrations were analyzed using (piecewise) linear regression models. Results: Linear temperature effects were found for glycine, C16-OH:C14:1-DC, and aspartic acid/asparagine. A 5 °C increase in temperature was associated with a 1.8% [95%-confidence interval: 0.3%; 3.3%] increase in glycine (5-day average), a 3.2% [0.1%; 6.3%] increase in C16-OH:C14:1-DC (lag of four days), and a −1.4% [−2.4%; −0.3%] decrease in aspartic acid/asparagine (lag of two days). Non-linear temperature effects were observed for alanine and total ketone bodies with breakpoint of 4 °C and 20 °C, respectively. Both a 5 °C decrease in temperature on colder days (<4 °C)and a 5 °C increase in temperature on warmer days (≥4 °C) were associated with a four day delayed increase in alanine by 6.6% [11.7; 1.8%] and 1.9% [0.3%; 3.4%], respectively. For ketone bodies we found immediate (0-day lag) increases of 4.2% [−0.5%; 9.1%] and 12.3% [0.1%; 26.0%] associated with 5 °C decreases on colder (<20 °C) days and 5 °C increases on warmer days (≥20 °C), respectively. Conclusions: We observed multiple effects of air temperature on

Polyurethane foam (PUF) disk passive samplers derived polychlorinated biphenyls (PCBs) concentrations in the ambient air of Bursa-Turkey: Spatial and temporal variations and health risk assessment.

PubMed

Birgül, Aşkın; Kurt-Karakus, Perihan Binnur; Alegria, Henry; Gungormus, Elif; Celik, Halil; Cicek, Tugba; Güven, Emine Can

2017-02-01

Polyurethane foam (PUF) passive samplers were employed to assess air concentrations of polychlorinated biphenyls (PCBs) in background, agricultural, semi-urban, urban and industrial sites in Bursa, Turkey. Samplers were deployed for approximately 2-month periods from February to December 2014 in five sampling campaign. Results showed a clear rural-agricultural-semi-urban-urban-industrial PCBs concentration gradient. Considering all sampling periods, ambient air concentrations of Σ 43 PCBs ranged from 9.6 to 1240 pg/m 3 at all sites with an average of 24.1 ± 8.2, 43.8 ± 24.4, 140 ± 190, 42.8 ± 24.6, 160 ± 280, 84.1 ± 105, 170 ± 150 and 280 ± 540 pg/m 3 for Mount Uludag, Uludag University Campus, Camlica, Bursa Technical University Osmangazi Campus, Hamitler, Agakoy, Kestel Organised Industrial District and Demirtas Organised Industrial District sampling sites, respectively. The ambient air PCB concentrations increased along a gradient from background to industrial areas by a factor of 1.7-11.4. 4-Cl PCBs (31.50-81.60%) was the most dominant homologue group at all sampling sites followed by 3-Cl, 7-Cl, 6-Cl and 5-Cl homologue groups. Sampling locations and potential sources grouped in principal component analysis. Results of PCA plots highlighted a large variability of the PCB mixture in air, hence possible related sources, in Bursa area. Calculated inhalation risk levels in this study indicated no serious adverse health effects. This study is one of few efforts to characterize PCB composition in ambient air seasonally and spatially for urban and industrial areas of Turkey by using passive samplers as an alternative sampling method for concurrent monitoring at multiple sites. Copyright © 2016 Elsevier Ltd. All rights reserved.

Coupling lead isotopes and element concentrations in epiphytic lichens to track sources of air emissions in the Alberta Oil Sands Region

EPA Science Inventory

A study was conducted that coupled use of element concentrations and lead (Pb) isotope ratios in the lichen Hypogymnia physodes collected during 2002 and 2008, to assess the impacts of air emissions from the Alberta Oil Sands Region (AOSR, Canada) mining and processing operations...

CONCENTRATION OF TETRACHLOROETHYLENE IN INDOOR AIR AT A FORMER DRY CLEANER FACILITY AS A FUNCTION OF SUBSURFACE CONTAMINATION: A CASE STUDY

EPA Science Inventory

A field study was performed to evaluate indoor air concentrations and vapor intrusion (VI) of tetrachloroethylene (PCE) and other chlorinated solvents at a commercial retail site in Dallas, TX. The building is approximately 40 years old and once housed a dry cleaning operation. R...

ComPAQS: a compact concentric UV/visible spectrometer, providing a new tool for air quality monitoring from space

NASA Astrophysics Data System (ADS)

Leigh, Roland J.; Whyte, C.; Cutter, M. A.; Lobb, D. R.; Monks, P. S.

2017-11-01

Under the first phase of the Centre for Earth Observation Instrumentation (CEOI), a breadboard demonstrator of a novel UV/VIS spectrometer has been developed. Using designs from Surrey Satellite Technology Ltd (SSTL) the demonstrator has been constructed and tested at the University of Leicester's Space Research Centre. This spectrometer provides an exceptionally compact instrument for differential optical absorption spectroscopy (DOAS) applications from LEO, GEO, HAP or ground-based platforms. Measurement of atmo spheric compounds with climate change or air quality implications is a key driver for the ground and space-based Earth Observation communities. Techniques using UV/VIS spectroscopy such as DOAS provide measurements of ozone profiles, aerosol optical depth, certain Volatile Organic Compounds, halogenated species, and key air quality parameters including tropospheric nitrogen dioxide. Compact instruments providing the necessary optical performance and spectral resolution are therefore a key enabling technology. The Compact Air Quality Spectrometer (CompAQS) features a concentric arrangement of a spherical meniscus lens, a concave spherical mirror and a suitable curved diffraction grating. This compact design provides efficiency and performance benefits over traditional concepts, improving the precision and spatial resolution available from space borne instruments with limited weight and size budgets. The breadboard spectrometer currently operating at the University of Leicester offers high throughput with a spectral range from 310 to 450 nm at 0.5nm(UV) to 1.0nm (visible) resolution, suitable for DOAS applications. The concentric design is capable of handling high relative apertures, owing to spherical aberration and coma being near zero at all surfaces. The design also provides correction for transverse chromatic aberration and distortion, in addition to correcting for the distortion called `smile' - the curvature of the slit image formed at each

Changes in Air CO2 Concentration Differentially Alter Transcript Levels of NtAQP1 and NtPIP2;1 Aquaporin Genes in Tobacco Leaves

PubMed Central

Secchi, Francesca; Schubert, Andrea; Lovisolo, Claudio

2016-01-01

The aquaporin specific control on water versus carbon pathways in leaves is pivotal in controlling gas exchange and leaf hydraulics. We investigated whether Nicotiana tabacum aquaporin 1 (NtAQP1) and Nicotiana tabacum plasma membrane intrinsic protein 2;1 (NtPIP2;1) gene expression varies in tobacco leaves subjected to treatments with different CO2 concentrations (ranging from 0 to 800 ppm), inducing changes in photosynthesis, stomatal regulation and water evaporation from the leaf. Changes in air CO2 concentration ([CO2]) affected net photosynthesis (Pn) and leaf substomatal [CO2] (Ci). Pn was slightly negative at 0 ppm air CO2; it was one-third that of ambient controls at 200 ppm, and not different from controls at 800 ppm. Leaves fed with 800 ppm [CO2] showed one-third reduced stomatal conductance (gs) and transpiration (E), and their gs was in turn slightly lower than in 200 ppm– and in 0 ppm–treated leaves. The 800 ppm air [CO2] strongly impaired both NtAQP1 and NtPIP2;1 gene expression, whereas 0 ppm air [CO2], a concentration below any in vivo possible conditions and specifically chosen to maximize the gene expression alteration, increased only the NtAQP1 transcript level. We propose that NtAQP1 expression, an aquaporin devoted to CO2 transport, positively responds to CO2 scarcity in the air in the whole range 0–800 ppm. On the contrary, expression of NtPIP2;1, an aquaporin not devoted to CO2 transport, is related to water balance in the leaf, and changes in parallel with gs. These observations fit in a model where upregulation of leaf aquaporins is activated at low Ci, while downregulation occurs when high Ci saturates photosynthesis and causes stomatal closure. PMID:27089333