The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Tom Harner - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of the particle infiltration efficiency of three passive Samplers and the PS-1 active air sampler
Atmospheric Environment, 2015Co-Authors: M. Z. Markovic, Sebastian Prokop, John Liggio, Ralf M Staebler, Tom HarnerAbstract:Abstract The particle infiltration efficiencies (PIE) of three passive and one active air Samplers were evaluated under field conditions. A wide-range particle spectrometer operating in the 250–4140 nm range was used to acquire highly temporally resolved particle-number and size distributions for the different Samplers compared to ambient air. Overall, three of the four evaluated Samplers were able to acquire a representative sample of ambient particles with PIEs of 91.5 ± 13.7% for the GAPS Network sampler, 103 ± 15.5% for the Lancaster University sampler, and 89.6 ± 13.4% for a conventional PS-1 high-volume active air sampler (Hi-Vol). Significantly (p = 0.05) lower PIE of 54 ± 8.0% was acquired for the passive sampler used under the MONET program. These findings inform the comparability and use of passive and active Samplers for measuring particle-associated priority chemicals in air.
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Evaluation of the particle infiltration efficiency of three passive Samplers and the PS-1 active air sampler
Atmospheric Environment, 2015Co-Authors: M. Z. Markovic, Sebastian Prokop, John Liggio, Ralf M Staebler, Tom HarnerAbstract:Abstract The particle infiltration efficiencies (PIE) of three passive and one active air Samplers were evaluated under field conditions. A wide-range particle spectrometer operating in the 250–4140 nm range was used to acquire highly temporally resolved particle-number and size distributions for the different Samplers compared to ambient air. Overall, three of the four evaluated Samplers were able to acquire a representative sample of ambient particles with PIEs of 91.5 ± 13.7% for the GAPS Network sampler, 103 ± 15.5% for the Lancaster University sampler, and 89.6 ± 13.4% for a conventional PS-1 high-volume active air sampler (Hi-Vol). Significantly (p = 0.05) lower PIE of 54 ± 8.0% was acquired for the passive sampler used under the MONET program. These findings inform the comparability and use of passive and active Samplers for measuring particle-associated priority chemicals in air.
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calibration and application of puf disk passive air Samplers for tracking polycyclic aromatic compounds pacs
Atmospheric Environment, 2013Co-Authors: Tom Harner, Susie Genualdi, Jessica Karpowicz, Lutz Ahrens, C Mihele, Jasmin Schuster, Jeanpierre Charland, J NarayanAbstract:Abstract Results are reported from a field calibration of the polyurethane foam (PUF) disk passive air sampler for measuring polycyclic aromatic compounds (PACs) in the atmosphere of the Alberta oil sands region of Canada. Passive Samplers were co-deployed alongside conventional high volume Samplers at three sites. The results demonstrate the ability of the PUF disk sampler to capture PACs, including polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs and parent and alkylated dibenzothiophenes. Both gas- and particle-phase PACs were captured with an average sampling rate of approximately 5 m3 day−1, similar to what has been previously observed for other semivolatile compounds. This is the first application of the PUF disk sampler for alkylated PAHs and dibenzothiophenes in air. The derived sampling rates are combined with estimates of the equilibrium partitioning of the PACs in the PUF disk Samplers to estimate effective sample air volumes for all targeted PACs. This information is then applied to the passive sampling results from two deployments across 17 sites in the region to generate spatial maps of PACs. The successful calibration of the sampler and development of the methodology for deriving air concentrations lends support to the application of this cost-effective and simple sampler in longer term studies of PACs in the oil sands region.
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field calibration of polyurethane foam puf disk passive air Samplers for pcbs and oc pesticides
Environmental Pollution, 2008Co-Authors: Chakra Chaemfa, Tom Harner, Jana Klanova, Jonathan L Barber, Tilman Gocht, Ivan Holoubek, Kevin C. JonesAbstract:Different passive air sampler (PAS) strategies have been developed for sampling in remote areas and for cost-effective simultaneous spatial mapping of POPs (persistent organic pollutants) over differing geographical scales. The polyurethane foam (PUF) disk-based PAS is probably the most widely used. In a PUF-based PAS, the PUF disk is generally mounted inside two stainless steel bowls to buffer the air flow to the disk and to shield it from precipitation and light. The field study described in this manuscript was conducted to: compare performance of 3 different designs of sampler; to further calibrate the sampler against the conventional active sampler; to derive more information on field-based uptake rates and equilibrium times of the Samplers. Samplers were also deployed at different locations across the field site, and at different heights up a meteorological tower, to investigate the possible influence of sampler location. Samplers deployed <5 m above ground, and not directly sheltered from the wind gave similar uptake rates. Small differences in dimensions between the 3 designs of passive sampler chamber had no discernable effect on accumulation rates, allowing comparison with previously published data.
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assessing the influence of meteorological parameters on the performance of polyurethane foam based passive air Samplers
Environmental Science & Technology, 2008Co-Authors: Jana Klanova, Jiři Kohoutek, Pavel Eupr, Tom HarnerAbstract:Polyurethane foam (PUF) disk passive air Samplers were evaluated under field conditions to assess the effect of temperature and wind speed on the sampling rate for polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs). Passive samples integrated over 28-day periods were compared to high-volume air samples collected for 24 h, every 7 days. This provided a large data set of 42 passive sampling events and 168 high-volume samples over a 3-year period, starting in October 2003. Average PUF disk sampling rates for gas-phase chemicals was ∼7 m3 d−1 and comparable to previous reports. The high molecular weight PAHs, which are mainly particle-bound, experienced much lower sampling rates of ∼0.7 m3 d−1. This small rate was attributed to the ability of the sampling chamber to filter out coarse particles with only the fine/ultrafine fraction capable of penetration and collection on the PUF disk. Passive sampler-derived data were converted to equivalent air vol...
Caroline Duchaine - One of the best experts on this subject based on the ideXlab platform.
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Bioaerosol Sampler Choice Should Consider Efficiency and Ability of Samplers to Cover Microbial Diversity
Applied and Environmental Microbiology, 2018Co-Authors: Hamza Mbareche, Guillaume J. Bilodeau, Marc Veillette, Caroline DuchaineAbstract:Bioaerosol studies tend to describe the microbial content and understand the aerosolization processes linked to diseases. Air Samplers are used to collect, identify and quantify bioaerosols. Studies comparing the performance of air Samplers have typically used a culture approach or have targeted a specific microorganism in laboratory settings. The objective of this study was to use environmental field samples to compare the efficiency of 3 high airflow rate Samplers for describing bioaerosol diversity using a next-generation sequencing approach. Two liquid cyclonic impactors and one electrostatic filter dry sampler were used in four wastewater treatment plants to target bacterial diversity and in five dairy farms to target fungal diversity. The dry electrostatic sampler was consistently more powerful in collecting more fungal and bacterial OTUs. Substantial differences in OTU abundance between liquid and dry sampling were revealed. The majority of the diversity revealed by dry electrostatic sampling was not identified using the cyclonic liquid impactors. The findings on this work suggest that the choice of a bioaerosol sampler should include information about the efficiency and ability of Samplers to cover microbial diversity. Although these results suggest that electrostatic filters result in better coverage of the microbial diversity amongst the tested air Samplers, further studies are needed to confirm this hypothesis. While it is difficult to determine a single universally optimal air sampler, this work provides an in-depth look at some of the considerations that are essential when choosing an air sampler for studying the microbial ecology of bioaerosols. Importance Associating bioaerosol exposure and health problems is challenging and adequate exposure monitoring is a priority for scientist in the field. Conclusions that can be drawn from bioaerosol exposure studies are highly dependent on the design of the study and the methodologies used. The air sampling strategy is the first methodological step leading to an accurate interpretation of what is present in the air. Applying new molecular approaches to evaluate the efficiency of the different types of Samplers used in the field is a necessary work around the traditional approaches and the biases they introduce to such studies. The results and conclusions provided in this manuscript should be taken in considerations when conducting a bioaerosol study.
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Bioaerosol Sampler Choice Should Consider Efficiency and Ability of Samplers To Cover Microbial Diversity.
Applied and environmental microbiology, 2018Co-Authors: Hamza Mbareche, Guillaume J. Bilodeau, Marc Veillette, Caroline DuchaineAbstract:Bioaerosol studies aim to describe the microbial content and increase understanding of the aerosolization processes linked to diseases. Air Samplers are used to collect, identify, and quantify bioaerosols. Studies comparing the performances of air Samplers have typically used a culture approach or have targeted a specific microorganism in laboratory settings. The objective of this study was to use environmental field samples to compare the efficiencies of 3 high-airflow-rate Samplers for describing bioaerosol diversity using a next-generation sequencing approach. Two liquid cyclonic impactors and one electrostatic filter dry sampler were used in four wastewater treatment plants to target bacterial diversity and in five dairy farms to target fungal diversity. The dry electrostatic sampler was consistently more powerful in collecting more fungal and bacterial operational taxonomic units (OTUs). Substantial differences in OTU abundances between liquid and dry sampling were revealed. The majority of the diversity revealed by dry electrostatic sampling was not identified using the cyclonic liquid impactors. The findings from this work suggest that the choice of a bioaerosol sampler should include information about the efficiency and ability of Samplers to cover microbial diversity. Although these results suggest that electrostatic filters result in better coverage of the microbial diversity among the tested air Samplers, further studies are needed to confirm this hypothesis. While it is difficult to determine a single universally optimal air sampler, this work provides an in-depth look at some of the considerations that are essential when choosing an air sampler for studying the microbial ecology of bioaerosols.IMPORTANCE Associating bioaerosol exposure and health problems is challenging, and adequate exposure monitoring is a priority for scientists in the field. Conclusions that can be drawn from bioaerosol exposure studies are highly dependent on the design of the study and the methodologies used. The air sampling strategy is the first methodological step leading to an accurate interpretation of what is present in the air. Applying new molecular approaches to evaluate the efficiencies of the different types of Samplers used in the field is necessary in order to circumvent traditional approaches and the biases they introduce to such studies. The results and conclusions provided in this paper should be taken in consideration when conducting a bioaerosol study.
Jana Klanova - One of the best experts on this subject based on the ideXlab platform.
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uncertainties in monitoring of svocs in air caused by within sampler degradation during active and passive air sampling
Atmospheric Environment, 2017Co-Authors: Lisa Melymuk, Pernilla Ohlinnizzetto, Roma Prokes, Pe Kukucka, Petra Přibylova, Simo Vojta, Jiři Kohoutek, Gerhard Lammel, Jana KlanovaAbstract:Degradation of semivolatile organic compounds (SVOCs) occurs naturally in ambient air due to reactions with reactive trace gases (e.g., ozone, NOx). During air sampling there is also the possibility for degradation of SVOCs within the air sampler, leading to underestimates of ambient air concentrations. We investigated the possibility of this sampling artifact in commonly used active and passive air Samplers for seven classes of SVOCs, including persistent organic pollutants (POPs) typically covered by air monitoring programs, as well as SVOCs of emerging concern. Two active air Samplers were used, one equipped with an ozone denuder and one without, to compare relative differences in mass of collected compounds. Two sets of passive Samplers were also deployed to determine the influence of degradation during longer deployment times in passive sampling. In active air Samplers, comparison of the two sampling configurations suggested degradation of particle-bound polycyclic aromatic hydrocarbons (PAHs), with concentrations up to 2× higher in the denuder-equipped sampler, while halogenated POPs did not have clear evidence of degradation. In contrast, more polar, reactive compounds (e.g., organophosphate esters and current use pesticides) had evidence of losses in the sampler with denuder. This may be caused by the denuder itself, suggesting sampling bias for these compounds can be created when typical air sampling apparatuses are adapted to limit degradation. Passive air Samplers recorded up to 4× higher concentrations when deployed for shorter consecutive sampling periods, suggesting that within-sampler degradation may also be relevant in passive air monitoring programs.
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field calibration of polyurethane foam puf disk passive air Samplers for pcbs and oc pesticides
Environmental Pollution, 2008Co-Authors: Chakra Chaemfa, Tom Harner, Jana Klanova, Jonathan L Barber, Tilman Gocht, Ivan Holoubek, Kevin C. JonesAbstract:Different passive air sampler (PAS) strategies have been developed for sampling in remote areas and for cost-effective simultaneous spatial mapping of POPs (persistent organic pollutants) over differing geographical scales. The polyurethane foam (PUF) disk-based PAS is probably the most widely used. In a PUF-based PAS, the PUF disk is generally mounted inside two stainless steel bowls to buffer the air flow to the disk and to shield it from precipitation and light. The field study described in this manuscript was conducted to: compare performance of 3 different designs of sampler; to further calibrate the sampler against the conventional active sampler; to derive more information on field-based uptake rates and equilibrium times of the Samplers. Samplers were also deployed at different locations across the field site, and at different heights up a meteorological tower, to investigate the possible influence of sampler location. Samplers deployed <5 m above ground, and not directly sheltered from the wind gave similar uptake rates. Small differences in dimensions between the 3 designs of passive sampler chamber had no discernable effect on accumulation rates, allowing comparison with previously published data.
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assessing the influence of meteorological parameters on the performance of polyurethane foam based passive air Samplers
Environmental Science & Technology, 2008Co-Authors: Jana Klanova, Jiři Kohoutek, Pavel Eupr, Tom HarnerAbstract:Polyurethane foam (PUF) disk passive air Samplers were evaluated under field conditions to assess the effect of temperature and wind speed on the sampling rate for polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs). Passive samples integrated over 28-day periods were compared to high-volume air samples collected for 24 h, every 7 days. This provided a large data set of 42 passive sampling events and 168 high-volume samples over a 3-year period, starting in October 2003. Average PUF disk sampling rates for gas-phase chemicals was ∼7 m3 d−1 and comparable to previous reports. The high molecular weight PAHs, which are mainly particle-bound, experienced much lower sampling rates of ∼0.7 m3 d−1. This small rate was attributed to the ability of the sampling chamber to filter out coarse particles with only the fine/ultrafine fraction capable of penetration and collection on the PUF disk. Passive sampler-derived data were converted to equivalent air vol...
Kevin C. Jones - One of the best experts on this subject based on the ideXlab platform.
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evidence and recommendations to support the use of a novel passive water sampler to quantify antibiotics in wastewaters
Environmental Science & Technology, 2013Co-Authors: Changer Chen, Guangguo Ying, Kevin C. JonesAbstract:A novel passive water sampler (diffusive gradients in thin-films for organics, o-DGT) was previously developed and successfully tested in the laboratory, but has not yet been validated in the field. Here, o-DGT Samplers were deployed in the influent and effluent of a typical UK wastewater treatment plant (WWTP); the influent was also sampled with a conventional automatic sampler (Auto) and by grab (Grab) sampling. All the samples were analyzed by LC-MS/MS for 40 target antibiotics (including 16 sulfonamides (SAs), 12 fluoroquinolones, 6 macrolides, 2 ionophores, 2 diaminopyimidines, 1 aminocoumarin, and 1 lincosamide). The diffusion coefficients (D) of these antibiotics in o-DGT, measured in the laboratory, ranged from 0.58 × 10–06 to 6.24 × 10–06 cm2 s–1. The derived surface area normalized sampling rates (RS/A, 0.54–5.74 mL d–1 cm–2) were comparable with those for another passive sampler called POCIS. Fourteen antibiotics were detected in the actively sampled water samples, with 10 of the 14 detected in...
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field calibration of polyurethane foam puf disk passive air Samplers for pcbs and oc pesticides
Environmental Pollution, 2008Co-Authors: Chakra Chaemfa, Tom Harner, Jana Klanova, Jonathan L Barber, Tilman Gocht, Ivan Holoubek, Kevin C. JonesAbstract:Different passive air sampler (PAS) strategies have been developed for sampling in remote areas and for cost-effective simultaneous spatial mapping of POPs (persistent organic pollutants) over differing geographical scales. The polyurethane foam (PUF) disk-based PAS is probably the most widely used. In a PUF-based PAS, the PUF disk is generally mounted inside two stainless steel bowls to buffer the air flow to the disk and to shield it from precipitation and light. The field study described in this manuscript was conducted to: compare performance of 3 different designs of sampler; to further calibrate the sampler against the conventional active sampler; to derive more information on field-based uptake rates and equilibrium times of the Samplers. Samplers were also deployed at different locations across the field site, and at different heights up a meteorological tower, to investigate the possible influence of sampler location. Samplers deployed <5 m above ground, and not directly sheltered from the wind gave similar uptake rates. Small differences in dimensions between the 3 designs of passive sampler chamber had no discernable effect on accumulation rates, allowing comparison with previously published data.
Olivier Witschger - One of the best experts on this subject based on the ideXlab platform.
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laboratory study of selected personal inhalable aerosol Samplers
Annals of Occupational Hygiene, 2010Co-Authors: P Gorner, Xavier Simon, Richard Wrobel, E Kauffer, Olivier WitschgerAbstract:Assessment of inhalable dust exposure requires reliable sampling methods in order to measure airborne inhalable particles’ concentrations. Many inhalable aerosol Samplers can be used but their performances widely vary and remain unknown in some cases. The sampling performance of inhalable Samplers is strongly dependent on particle size and ambient air velocity. Five inhalable aerosol Samplers have been studied in two laboratory wind tunnels using polydisperse glass-beads’ test aerosol. Samplers tested were IOM sampler (UK), two versions of CIP 10-I sampler, v1 and v2 (F), 37-mm closed face cassette sampler (USA), 37-mm cassette fitted up with an ACCU-CAP insert (USA), and Button sampler (USA). Particle size-dependent sampling efficiencies were measured in a horizontal wind tunnel under a 1 m s 21 wind velocity and in a vertical tunnel under calm air, using a specific method with Coulter counter particle size number distribution determinations. Compared with CEN–ISO–ACGIH sampling criteria for inhalable dust, the experimental results show fairly high sampling efficiency for the IOM and CIP 10-I v2 Samplers and slightly lower efficiencies for the Button and CIP 10-I v1 Samplers. The closed face cassette (4-mm orifice) produced the poorest performances of all the tested Samplers. This can be improved by using the ACCU-CAP internal capsule, which prevents inner wall losses inside the cassette. Significant differences between moving air and calm air sampling efficiency were observed for all the studied Samplers.
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Performance of personal inhalable aerosol Samplers in very slowly moving air when facing the aerosol source
Annals of Occupational Hygiene, 2004Co-Authors: Olivier Witschger, S.a. Grinshpun, S. Fauvel, G. BassoAbstract:While personal aerosol Samplers have been characterized primarily based on wind tunnel tests conducted at relatively high wind speeds, modern indoor occupational environments are usually represented by very slow moving air. Recent surveys suggest that elevated levels of occupational exposure to inhalable airborne particles are typically observed when the worker, operating in the vicinity of the dust source, faces the source. Thus, the first objective of this study was to design and test a new, low cost experimental protocol for measuring the sampling efficiency of personal inhalable aerosol Samplers in the vicinity of the aerosol source when the Samplers operate in very slowly moving air. In this system, an aerosol generator, which is located in the centre of a room-sized non-ventilated chamber, continuously rotates and omnidirectionally disperses test particles of a specific size. The test and reference Samplers are equally distributed around the source at the same distance from the centre and operate in parallel (in most of our experiments, the total number of simultaneously operating Samplers was 15). Radial aerosol transport is driven by turbulent diffusion and some natural convection. For each specific particle size and the sampler, the aerosol mass concentration is measured by weighing the collection filter. The second objective was to utilize the new protocol to evaluate three widely used aerosol Samplers: the IOM Personal Inhalable Sampler, the Button Personal Inhalable Aerosol Sampler and the 25 mm Millipore filter holder (closed-face C25 cassette). The sampling efficiencies of each instrument were measured with six particle fractions, ranging from 6.9 to 76.9 μm in their mass median aerodynamic diameter. The Button Sampler efficiency data demonstrated a good agreement with the standard inhalable convention and especially with the low air movement inhalabilty curve. The 25 mm filter holder was found to considerably under-sample the particles larger than 10 μm; its efficiency did not exceed 7% for particles of 40-100 μm. The IOM Sampler facing the source was found to over-sample compared with the data obtained previously with a slowly rotating, freely suspended sampler in a low air movement environment. It was also found that the particle wall deposition in the IOM metallic cartridge was rather significant and particle size-dependent. For each sampler (IOM, Button and C25) the precision was characterized through the relative standard deviation (RSD) of the aerosol concentration obtained with identical Samplers in a specific experiment. The average RSD was 14% for the IOM Sampler, 11% for the Button Sampler and 35% for the 25 mm filter cassette. A separate set of experiments, performed with the Simplified Torso showed that in very slowly moving air a personal sampler can be adequately evaluated even when it is not attached to a body but freely suspended (confirming the data reported previously).
