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Thomas M Peters - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of the alphasense Optical Particle Counter opc n2 and the grimm portable aerosol spectrometer pas 1 108
    Aerosol Science and Technology, 2016
    Co-Authors: Sinan Sousan, Laura Hallett, Kirsten A Koehler, Thomas M Peters
    Abstract:

    AbstractWe compared the performance of a low-cost (∼$500), compact Optical Particle Counter (OPC, OPC-N2, Alphasense) to another OPC (PAS-1.108, Grimm Technologies) and reference instruments. We measured the detection efficiency of the OPCs by size from 0.5 to 5 µm for monodispersed, polystyrene latex (PSL) spheres. We then compared number and mass concentrations measured with the OPCs to those measured with reference instruments for three aerosols: salt, welding fume, and Arizona road dust. The OPC-N2 detection efficiency was similar to the PAS-1.108 for Particles larger than 0.8 µm (minimum of 79% at 1 µm and maximum of 101% at 3 µm). For 0.5-µm Particles, the detection efficiency of the OPC-N2 was underestimated at 78%, whereas PAS-1.108 overestimated concentrations by 183%. The mass concentrations from the OPCs were linear (r ≥ 0.97) with those from the reference instruments for all aerosols, although the slope and intercept were different. The mass concentrations were overestimated for dust (OPC-N2, ...

  • Evaluation of the Alphasense Optical Particle Counter (OPC-N2) and the Grimm portable aerosol spectrometer (PAS-1.108)
    Aerosol science and technology : the journal of the American Association for Aerosol Research, 2016
    Co-Authors: Sinan Sousan, Kirsten Koehler, Laura Hallett, Thomas M Peters
    Abstract:

    We compared the performance of a low-cost (∼$500), compact Optical Particle Counter (OPC, OPC-N2, Alphasense) to another OPC (PAS-1.108, Grimm Technologies) and reference instruments. We measured the detection efficiency of the OPCs by size from 0.5 to 5 μm for monodispersed, polystyrene latex (PSL) spheres. We then compared number and mass concentrations measured with the OPCs to those measured with reference instruments for three aerosols: salt, welding fume and Arizona road dust. The OPC-N2 detection efficiency for monodispersed was similar to the PAS-1.108 for Particles larger than 0.8 μm (minimum of 79% at 1 μm and maximum of 101% at 3 μm). For 0.5-μm Particles, the detection efficiency of OPCN2 was underestimated at 78%, whereas PAS-1.108 overestimated concentrations by 183%. The mass concentrations from the OPCs were linear (r ≥ 0.97) with those from the reference instruments for all aerosols, although the slope and intercept were different. The mass concentrations were overestimated for dust (OPC-N2, slope = 1.6; PAS-1.108, slope = 2.7) and underestimated for welding fume (OPC-N2, slope = 0.05; PAS-1.108, slope = 0.4). The coefficient of variation (CV, precision) for OPC-N2 for all experiments was between 4.2% and 16%. These findings suggest that, given site-specific calibrations, the OPC-N2 can provide number and mass concentrations similar to the PAS-1.108 for Particles larger than 1 μm.

  • Evaluation of the Alphasense Optical Particle Counter (OPC-N2) and the Grimm portable aerosol spectrometer (PAS-1.108)
    2016
    Co-Authors: Sinan Sousan, Kirsten Koehler, Laura Hallett, Thomas M Peters
    Abstract:

    We compared the performance of a low-cost (∼$500), compact Optical Particle Counter (OPC, OPC-N2, Alphasense) to another OPC (PAS-1.108, Grimm Technologies) and reference instruments. We measured the detection efficiency of the OPCs by size from 0.5 to 5 µm for monodispersed, polystyrene latex (PSL) spheres. We then compared number and mass concentrations measured with the OPCs to those measured with reference instruments for three aerosols: salt, welding fume, and Arizona road dust. The OPC-N2 detection efficiency was similar to the PAS-1.108 for Particles larger than 0.8 µm (minimum of 79% at 1 µm and maximum of 101% at 3 µm). For 0.5-µm Particles, the detection efficiency of the OPC-N2 was underestimated at 78%, whereas PAS-1.108 overestimated concentrations by 183%. The mass concentrations from the OPCs were linear (r ≥ 0.97) with those from the reference instruments for all aerosols, although the slope and intercept were different. The mass concentrations were overestimated for dust (OPC-N2, slope = 1.6; PAS-1.108, slope = 2.7) and underestimated for welding fume (OPC-N2, slope = 0.05; PAS-1.108, slope = 0.4). The coefficient of variation (CV, precision) for OPC-N2 for all experiments was between 4.2% and 16%. These findings suggest that, given site-specific calibrations, the OPC-N2 can provide number and mass concentrations similar to the PAS-1.108 for Particles larger than 1 µm. Copyright © 2016 American Association for Aerosol Research

  • use of a condensation Particle Counter and an Optical Particle Counter to assess the number concentration of engineered nanoParticles
    Journal of Occupational and Environmental Hygiene, 2010
    Co-Authors: Linda H Schmoll, Thomas M Peters, Patrick T Oshaughnessy
    Abstract:

    There is a need to evaluate nanoParticle (< 100 nm) exposures in occupational settings. However, portable instruments do not size segregate Particles in that size range. A proxy method for determining nanoParticle count concentrations involves subtracting counts made with a condensation Particle Counter (CPC) from those of an Optical Particle Counter/sizer (OPC), resulting in an estimation of “very fine” Particles < 300 nm, where 300 nm is the OPC lower detection limit. However, to determine size distributions from which Particles < 100 nm may be estimated, the resulting count of Particles < 300 nm can be used as an additional channel of count data in addition to those obtained from the OPC. To test these methods, the very fine number concentrations determined using a CPC and OPC were compared with those from SMPS measurements and were used to verify the accuracy of a very fine Particle number concentration determined by an OPC and CPC. Two “size-distribution” methods, weighted-average and log-probit, wer...

  • relationships among Particle number surface area and respirable mass concentrations in automotive engine manufacturing
    Journal of Occupational and Environmental Hygiene, 2008
    Co-Authors: William A Heitbrink, Douglas E Evans, Bon Ki Ku, Andrew D Maynard, Thomas J Slavin, Thomas M Peters
    Abstract:

    This study investigated the relationships between Particle number, surface area, and respirable mass concentration measured simultaneously in a foundry and an automotive engine machining and assembly center. Aerosol concentrations were measured throughout each plant with a condensation Particle Counter for number concentration, a diffusion charger for active surface area concentration, and an Optical Particle Counter for respirable mass concentration. At selected locations, Particle size distributions were characterized with the Optical Particle Counter and an electrical low pressure impactor. Statistical analyses showed that active surface area concentration was correlated with ultrafine Particle number concentration and weakly correlated with respirable mass concentration. Correlation between number and active surface area concentration was stronger during winter (R 2 = 0.6 for both plants) than in the summer (R 2 = 0.38 and 0.36 for the foundry and engine plant respectively). The stronger correlation i...

G Biskos - One of the best experts on this subject based on the ideXlab platform.

Sinan Sousan - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of the alphasense Optical Particle Counter opc n2 and the grimm portable aerosol spectrometer pas 1 108
    Aerosol Science and Technology, 2016
    Co-Authors: Sinan Sousan, Laura Hallett, Kirsten A Koehler, Thomas M Peters
    Abstract:

    AbstractWe compared the performance of a low-cost (∼$500), compact Optical Particle Counter (OPC, OPC-N2, Alphasense) to another OPC (PAS-1.108, Grimm Technologies) and reference instruments. We measured the detection efficiency of the OPCs by size from 0.5 to 5 µm for monodispersed, polystyrene latex (PSL) spheres. We then compared number and mass concentrations measured with the OPCs to those measured with reference instruments for three aerosols: salt, welding fume, and Arizona road dust. The OPC-N2 detection efficiency was similar to the PAS-1.108 for Particles larger than 0.8 µm (minimum of 79% at 1 µm and maximum of 101% at 3 µm). For 0.5-µm Particles, the detection efficiency of the OPC-N2 was underestimated at 78%, whereas PAS-1.108 overestimated concentrations by 183%. The mass concentrations from the OPCs were linear (r ≥ 0.97) with those from the reference instruments for all aerosols, although the slope and intercept were different. The mass concentrations were overestimated for dust (OPC-N2, ...

  • Evaluation of the Alphasense Optical Particle Counter (OPC-N2) and the Grimm portable aerosol spectrometer (PAS-1.108)
    Aerosol science and technology : the journal of the American Association for Aerosol Research, 2016
    Co-Authors: Sinan Sousan, Kirsten Koehler, Laura Hallett, Thomas M Peters
    Abstract:

    We compared the performance of a low-cost (∼$500), compact Optical Particle Counter (OPC, OPC-N2, Alphasense) to another OPC (PAS-1.108, Grimm Technologies) and reference instruments. We measured the detection efficiency of the OPCs by size from 0.5 to 5 μm for monodispersed, polystyrene latex (PSL) spheres. We then compared number and mass concentrations measured with the OPCs to those measured with reference instruments for three aerosols: salt, welding fume and Arizona road dust. The OPC-N2 detection efficiency for monodispersed was similar to the PAS-1.108 for Particles larger than 0.8 μm (minimum of 79% at 1 μm and maximum of 101% at 3 μm). For 0.5-μm Particles, the detection efficiency of OPCN2 was underestimated at 78%, whereas PAS-1.108 overestimated concentrations by 183%. The mass concentrations from the OPCs were linear (r ≥ 0.97) with those from the reference instruments for all aerosols, although the slope and intercept were different. The mass concentrations were overestimated for dust (OPC-N2, slope = 1.6; PAS-1.108, slope = 2.7) and underestimated for welding fume (OPC-N2, slope = 0.05; PAS-1.108, slope = 0.4). The coefficient of variation (CV, precision) for OPC-N2 for all experiments was between 4.2% and 16%. These findings suggest that, given site-specific calibrations, the OPC-N2 can provide number and mass concentrations similar to the PAS-1.108 for Particles larger than 1 μm.

  • Evaluation of the Alphasense Optical Particle Counter (OPC-N2) and the Grimm portable aerosol spectrometer (PAS-1.108)
    2016
    Co-Authors: Sinan Sousan, Kirsten Koehler, Laura Hallett, Thomas M Peters
    Abstract:

    We compared the performance of a low-cost (∼$500), compact Optical Particle Counter (OPC, OPC-N2, Alphasense) to another OPC (PAS-1.108, Grimm Technologies) and reference instruments. We measured the detection efficiency of the OPCs by size from 0.5 to 5 µm for monodispersed, polystyrene latex (PSL) spheres. We then compared number and mass concentrations measured with the OPCs to those measured with reference instruments for three aerosols: salt, welding fume, and Arizona road dust. The OPC-N2 detection efficiency was similar to the PAS-1.108 for Particles larger than 0.8 µm (minimum of 79% at 1 µm and maximum of 101% at 3 µm). For 0.5-µm Particles, the detection efficiency of the OPC-N2 was underestimated at 78%, whereas PAS-1.108 overestimated concentrations by 183%. The mass concentrations from the OPCs were linear (r ≥ 0.97) with those from the reference instruments for all aerosols, although the slope and intercept were different. The mass concentrations were overestimated for dust (OPC-N2, slope = 1.6; PAS-1.108, slope = 2.7) and underestimated for welding fume (OPC-N2, slope = 0.05; PAS-1.108, slope = 0.4). The coefficient of variation (CV, precision) for OPC-N2 for all experiments was between 4.2% and 16%. These findings suggest that, given site-specific calibrations, the OPC-N2 can provide number and mass concentrations similar to the PAS-1.108 for Particles larger than 1 µm. Copyright © 2016 American Association for Aerosol Research

Masahiko Hayashi - One of the best experts on this subject based on the ideXlab platform.

  • Development of a polarization Optical Particle Counter capable of aerosol type classification
    Atmospheric Environment, 2014
    Co-Authors: Hiroshi Kobayashi, Masahiko Hayashi, Koichi Shiraishi, Yoshinobu Nakura, Takayuki Enomoto, Kazuhiko Miura, Hiroshi Takahashi, Yasuhito Igarashi, Hiroaki Naoe, Naoki Kaneyasu
    Abstract:

    Abstract We developed a polarization Optical Particle Counter (POPC) for measuring the concentrations of aerosol types, which were classified using polarization information from Particle-scattered light. Polarization sensors that detect P and S polarization components of scattered light were placed at a scattering angle of 120°. The polarization ratio is calculated as the ratio of the S component to the sum of the S and P components, and it is used to help distinguish proposed aerosol types. The POPC field observation was conducted in Fukuoka, located in the western part of Japan, in 2012. The classification rule for three aerosol types (mineral dust, air pollution, and sea-salt Particles) was determined empirically on the basis of measurements during typical conditions dominated by each aerosol type. The mass concentration of each aerosol type was estimated from the POPC measurement with some assumptions. The results indicate independent seasonal variation in each aerosol mass concentration. Using black carbon as an indicator of anthropogenic aerosols, we show a correlation of 0.770 with our estimated pollution aerosol type.

  • development of polarization Optical Particle Counter to detect Particle shape information
    Lidar Remote Sensing for Environmental Monitoring XIII, 2012
    Co-Authors: Hiroshi Kobayashi, Masahiko Hayashi, Yoshinobu Nakura, Takayuki Enomoto, Kazuhiko Miura, Hiroshi Takahashi, Yasuhito Igarashi, Hiroaki Naoe, Tomoaki Nishizawa, Nobuo Sugimoto
    Abstract:

    Polarization Optical Particle Counter (POPC) capable of measuring Particle shape or sphericity was developed, which uses detection of polarization of light scattered by Particles. Sensors that detected P and S polarization components are incorporated at scattering angle of 120˚ in addition to ordinary sensor located at the angle of 60˚. The Particle size is derived from the pulse height detected with the ordinary sensor. The size thresholds were determined by measurements of PSL standard Particles. Polarization of Particle is calculated as the ratio of S polarization component to the sum of all components. The POPC field observations were started in Fukuoka, Japan on 15 March 2012 and in Matsue, Japan on 28 February 2012. Air pollution with high Particle number concentration was observed in Fukuoka on 11 April. In that time, the Particles with polarization lower than 0.3 constituted 90% of Particles in the size range from 0.5 µm to 3 µm and 70-90% of those from 3 µm to 5 µm. Most of the atmospheric aerosol Particles were consisted of spherical Particles. Significant Asian dust transport was observed in Fukuoka on from 31 March to 1 April. The Particles with polarization lower than 0.3 constituted 80% of those from 0.5 µm to 1 µm, 55-65% of those from 1 µm to 5µm. The increase of the ratio of non-spherical Particles to all Particles in Asian dust event was confirmed. The POPC thus is capable of measuring Particle shape as well as size for each individual Particle.

  • characteristics of aerosol and cloud Particle size distributions in the tropical tropopause layer measured with Optical Particle Counter and lidar
    Atmospheric Chemistry and Physics, 2007
    Co-Authors: Suginori Iwasaki, Masahiko Hayashi, K Maruyama, Shinya Ogino, H Ishimoto, Yoshihiro Tachibana, Atsushi Shimizu, Ichiro Matsui, Nobuo Sugimoto
    Abstract:

    An Optical Particle Counter (OPC) is used in con- junction with lidar measurements to examine the characteris- tics of the Particle size distribution in cirrus cloud in the trop- ical tropopause layer (TTL) over Thailand where the TTL is defined as the height at which temperature is lower than 75 C in this paper. Of 11 OPC launches, cirrus cloud was detected at 10-15 km high on 7 occasions, cirrus was de- tected in the TTL in 6 cases, and simultaneous OPC and lidar measurements were made on two occasions. Comparison of lidar and OPC measurements reveal that the cloud heights of cirrus in the TTL varies by several hundred meters over distances of tens kilometers; hence the height is not always horizontally uniform. The mode radii of Particles constitut- ing the clouds are estimated by lidar and OPC measurements to be less than approximately 10µm. The regression lines of the Particle size distribution with and without cirrus cloud exhibit similar features at equivalent radii of <0.8µm. En- hancement in the integrated number concentration at radii greater than 0.8µm indicates that liquid Particles tend to be

  • characteristics of Particle size distributions in the tropical tropopause based on Optical Particle Counter and lidar measurements
    Atmospheric Chemistry and Physics, 2007
    Co-Authors: Suginori Iwasaki, Masahiko Hayashi, Nobuo Sugimoto, K Maruyama, Shinya Ogino, H Ishimoto, Yoshihiro Tachibana, Atsushi Shimizu, Ichiro Matsui, K Yamashita
    Abstract:

    An Optical Particle Counter (OPC) is used in conjunction with lidar measurements to examine the characteristics of the Particle size distribution in cirrus cloud at the tropical tropopause (TT) over Thailand. Of 11 OPC launches, cirrus cloud was detected at 10?15 km high on 7 occasions, cirrus was detected at the TT in 6 cases, and simultaneous OPC and lidar measurements were made on two occasions. Comparison of lidar and OPC measurements reveal that the cloud height of cirrus in the TT varies by several hundred meters over distances of tens kilometers; hence the height is not horizontally uniform. The mode radii of Particles constituting the clouds are estimated by lidar and OPC measurements to be less than approximately 10 ?m. The regression lines of the Particle size distribution with and without cirrus cloud exhibit similar features at equivalent radii of <0.7 ?m. Enhancement in the integrated number concentration at radii greater than 0.7 ?m indicates that liquid Particles tend to be frozen at a radius of 0.7 ?m, with cirrus clouds above 10 km exhibiting similar features. In addition, common features of cirrus clouds at the TT include a local maximum in the Particle size distribution at 2.0 ?m and a peak between 0.5 ?m and 1.7 ?m in the ratio of the standard deviation of count values to that of the Poisson distribution of the averaged count values. Each feature implies that all ice Particles in the clouds may be nucleated by the same mechanism and Particles in this size range are actively frozen at the TT. These parameters are thus good indicators for checking the results of cirrus cloud models in the TT.

  • balloon borne Optical Particle Counter for stratospheric observation
    Review of Scientific Instruments, 2003
    Co-Authors: Takeshi Kasai, Masahiko Hayashi, Masayoshi Tsuchiya, Katsumi Takami, Yasunobu Iwasaka
    Abstract:

    This article presents the ambient air pressure effects on a balloon borne Optical Particle Counter (an aerosol sonde: AS) equipped with a laser as the light source, and the relevant measures to overcome these effects. To investigate the effects of ambient air pressure varying from 1013 to 10 hPa (from ground level to an altitude of about 30 km) and estimate the general performance of the AS, a novel versatile pressure-variable test chamber was constructed equipped with a built-in nebulizer system. To overcome the direct effect of ambient air pressure on the sensing zone occurring when an open cavity laser (an external mirror-type laser) is used, a flat parallel window was adopted in place of the Brewster window, and in addition, only the laser tube was sealed in an aluminum tube under normal atmospheric pressure. Consequently, the laser power change was suppressed to within ±0.5% for the pressure variation range. To overcome the large dependence in the aerosol sampling flow rate on the ambient air pressur...

S Bezantakos - One of the best experts on this subject based on the ideXlab platform.