The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Martin Schnaiter - One of the best experts on this subject based on the ideXlab platform.
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Fluorescent Biological aerosol particles measured with the Waveband Integrated Bioaerosol Sensor WIBS-4: laboratory tests combined with a one year field study
Atmospheric Chemistry and Physics, 2013Co-Authors: E. Toprak, Martin SchnaiterAbstract:Abstract. In this paper bioaerosol measurements conducted with the Waveband Integrated Bioaerosol Sensor mark 4 (WIBS-4) are presented. The measurements comprise aerosol chamber characterization experiments and a one-year ambient measurement period at a semi-rural site in South Western Germany. This study aims to investigate the sensitivity of WIBS-4 to Biological and non-Biological Aerosols and detection of Biological particles in the ambient aerosol. Several types of Biological and non-Biological aerosol samples, including fungal spores, bacteria, mineral dust, ammonium sulphate, combustion soot, and fluorescent polystyrene spheres, were analyzed by WIBS-4 in the laboratory. The results confirm the sensitivity of the ultraviolet light-induced fluorescence (UV-LIF) method to Biological fluorophores and show the good discrimination capabilities of the two excitation wavelengths/detection wavebands method applied in WIBS-4. However, a weak cross-sensitivity to non-Biological fluorescent interferers remains and is discussed in this paper. All the laboratory studies have been undertaken in order to prepare WIBS-4 for ambient aerosol measurements. According to the one-year ambient aerosol study, number concentration of fluorescent Biological aerosol particles (FBAP) show strong seasonal and diurnal variability. The highest number concentration of FBAP was measured during the summer term and decreased towards the winter period when colder and drier conditions prevail. Diurnal FBAP concentrations start to increase after sunset and reach maximum values during the late night and early morning hours. On the other hand, the total aerosol number concentration was almost always higher during daytime than during nighttime and a sharp decrease after sunset was observed. There was no correlation observed between the FBAP concentration and the meteorological parameters temperature, precipitation, wind direction and wind speed. However, a clear correlation was identified between the FBAP number concentration and the relative humidity. Humidity-controlled release mechanisms of some fungal spore species are discussed as a possible explanation.
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Fluorescent Biological aerosol particles (FBAPs) measured with the Waveband Integrated Bioaerosol Sensor WIBS-4: laboratory tests combined with a one year field study
2012Co-Authors: E. Toprak, Martin SchnaiterAbstract:Abstract. In this paper bioaerosol measurements conducted with the Waveband Integrated Bioaerosol Sensor mark 4 (WIBS-4) are presented. The measurements comprise aerosol chamber characterization experiments and a one-year ambient measurement period at a semi-rural site in South Western Germany. This study aims to investigate the sensitivity of WIBS-4 to Biological and non-Biological Aerosols, performance of WIBS-4 for discrimination of several types of Aerosols, and the detection and identification of Biological particles in the ambient aerosol. Several types of Biological and non-Biological aerosol samples including spores, bacteria, pollen, mineral dust, ammonium sulphate, combustion soot, and fluorescent polystyrene spheres were analysed by WIBS-4 in the laboratory. The results confirm the sensitivity of the Ultra Violet Light Induced Fluorescence (UV-LIF) method to Biological fluorophores and show the good discrimination capabilities of the two wavelengths excitation/two wavebands detection method applied in WIBS-4. However, a weak cross-sensitivity to non-Biological fluorescent interferers remains and is discussed in this paper. All the laboratory studies have been undertaken in order to prepare WIBS-4 for ambient aerosol measurements. According to the one year ambient aerosol study, number concentration of fluorescent Biological aerosol particles (FBAP) show strong seasonal and diurnal variability. The highest number concentration of FBAP was measured during the summer term and it decreases towards the winter period when colder and drier conditions are prevailing. Diurnal FBAP concentrations start to increase after sunset and reach maximum values during the late night and early morning hours. On the other hand the total aerosol number concentration was always higher during day time than during night time and a sharp decrease after sunset was observed. There was no correlation observed between the FBAP concentration and the meteorological parameters temperature, precipitation, wind direction and wind speed. However a clear correlation was identified between the FBAP number concentration and the relative humidity. Humidity controlled release mechanisms of some fungal spore species are discussed as a possible explanation.
Richard K. Chang - One of the best experts on this subject based on the ideXlab platform.
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dual wavelength excitation single particle fluorescence spectrometer particle sorter for real time measurement of organic carbon and Biological Aerosols
Proceedings of SPIE the International Society for Optical Engineering, 2008Co-Authors: Yong-le Pan, Steven C. Hill, Ron G Pinnick, Hermes Huang, Richard K. ChangAbstract:We report the development of a Single-Particle Fluorescence Spectrometer (SPFS) system capable of measuring two UV-laser excited fluorescence spectra from a single particle on-the-fly. The two dispersed fluorescence spectra are obtained from excitation by two lasers at different wavelengths (263 nm and 351 nm). The SPFS samples single particles with sizes primarily in the 1–10 µm range. The fluorescence spectra are recorded from 280 nm to 600 nm (in 20 channels) for 263 nm excitation and from 370 nm to 700 nm (in 22 channels) for 351 nm excitation. The elastic scattering (channel 4 and 9) is also recorded for sizing each particle. A time stamp for single particles is marked with a variable time interval resolution from 10 ms to 10 minutes. The SPFS employs a virtual-impactor concentrator to concentrate respirable-sized particles with a resulting (size-dependent) effective flow rate of around 100 liters/min. The SPFS can measure single-particle spectra at a maximum rate of 90,000/sec, although the highest rates we have experienced for the ambient are only several hundred/sec. When the SPFS is combined with an aerodynamic deflector (puffer) to sort particles according to their fluorescence spectral characteristics, the SPFS/puffer system can selectively deflect and collect an enriched sample of targeted particles (at rates limited by the puffer) of 1200 particles/sec, for further examination. In laboratory tests, aerosol particles with similar UV-LIF spectra (e.g. B. subtilis and E.coli) are puffed into the reservoir of a micro-fluidic cell, where fluorescent-labeled antibodies bind to them and were classified by their labeled fluorescence. Measurements of the background ambient aerosol with the SPFS system made at sites with different regional climate (Connecticut, Maryland, and New Mexico) were clustered (unstructured hierarchical analysis) into 8-10 groups, with over 90% of all the fluorescent particles contained within these clusters (threshold dot product=0.9). However, the percentage of Aerosols in each profile differed by sampling location. The unique features and performance of the SPFS/puffer system compared to other fluorescence-based bio-aerosol sensors will be discussed, with emphasis on reduction of false alarm rates.
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single particle laser induced fluorescence spectra of Biological and other organic carbon Aerosols in the atmosphere measurements at new haven connecticut and las cruces new mexico
Journal of Geophysical Research, 2007Co-Authors: Yong-le Pan, Steven C. Hill, R G Pinnick, James M Rosen, Richard K. ChangAbstract:[1] This study focuses on organic carbon (OC) Aerosols, including natural Biological Aerosols, in the Earth's troposphere, and on laser-induced fluorescence (LIF) spectral methods for studying these Aerosols. LIF spectra of atmospheric OC and Biological Aerosols (having diameters greater than approximately 3 μm) measured at New Haven, Connecticut, and Las Cruces, New Mexico, are reported. A hierarchical clustering method was used to cluster approximately 90% of the single-particle LIF spectra into 8-10 groups. Some of these groups have spectra that are similar to spectra of some important classes of atmospheric aerosol, such as humic/fulvic acids and humic-like substances, bacteria, cellulose, marine aerosol, and polycyclic aromatic hydrocarbons (PAH). A comparison with previous measurements made at Adelphi, Maryland, reveals that the most highly populated clusters found at Adelphi, and some of the less populated ones, also appear in the LIF spectra at New Haven and Las Cruces, even though the regional climates at these locations is different (New England/Atlantic Coastal, for New Haven and Adelphi, and Chihuahuan Desert for Las Cruces), and the measurements were made in different seasons. The results are consistent with some (perhaps most) of the fluorors in OC and Biological atmospheric Aerosols being common to these three sites. On average, spectra characteristic of humic/fulvic acids and humic-like substances (HULIS) comprise 28-43% of fluorescent particles at all three sites; whereas cellulose-like spectra contribute only 1 -3%.
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Optical scattering by Biological Aerosols: experimental and computational results on spore simulants
Optics express, 2006Co-Authors: O. I. Sindoni, Yong-le Pan, Rosalba Saija, Maria Antonia Iatì, Ferdinando Borghese, Paolo Denti, Gustavo E. Fernandes, Richard K. ChangAbstract:We present both a computational and an experimental approach to the problem of Biological aerosol characterization, joining the expertises reached in the field of theoretical optical scattering by complex, arbitrary shaped particles (multipole expansion of the electromagnetic fields and Transition Matrix), and a novel experimental technique based on two-dimensional angular optical scattering (TAOS). The good agreement between experimental and computational results, together with the possibility for a laboratory single-particle angle-resolved investigation, opens a new scenario in Biological particle modelling, and might have major implications for a rapid discrimination of airborne particles.
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Single-shot fluorescence spectra of single micron-sized particles for the characterization of Biological Aerosols
Technical Digest. Summaries of papers presented at the Conference on Lasers and Electro-Optics. Postconference Edition. CLEO '99. Conference on Lasers, 1Co-Authors: Yong-le Pan, Stephen Holler, Richard K. Chang, Steven C. Hill, Ronald G. Pinnick, S. Niles, J.r. BottigerAbstract:Summary form only given. Airborne Biological particles are minor but important component of Earth's atmosphere. They can cause disease in humans, animals, and plants. Therefore, the rapid real-time measurements of fluorescence spectra of airborne particles for the discrimination and characterization among Biological Aerosols would be useful. In this paper a new method for real-time measurement of reproducible, high signal-to-noise ratio, single-shot UV laser excited fluorescence spectra of various flowing individual Biological Aerosols is described.
Giuseppe Frenguelli - One of the best experts on this subject based on the ideXlab platform.
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Thunderstorm‐asthma and pollen allergy
Allergy, 2007Co-Authors: Gennaro D'amato, G. Liccardi, Giuseppe FrenguelliAbstract:Thunderstorms have been linked to asthma epidemics, especially during the pollen seasons, and there are descriptions of asthma outbreaks associated with thunderstorms, which occurred in several cities, prevalently in Europe (Birmingham and London in the UK and Napoli in Italy) and Australia (Melbourne and Wagga Wagga). Pollen grains can be carried by thunderstorm at ground level, where pollen rupture would be increased with release of allergenic Biological Aerosols of paucimicronic size, derived from the cytoplasm and which can penetrate deep into lower airways. In other words, there is evidence that under wet conditions or during thunderstorms, pollen grains may, after rupture by osmotic shock, release into the atmosphere part of their content, including respirable, allergen-carrying cytoplasmic starch granules (0.5-2.5 microm) or other paucimicronic components that can reach lower airways inducing asthma reactions in pollinosis patients. The thunderstorm-asthma outbreaks are characterized, at the beginning of thunderstorms by a rapid increase of visits for asthma in general practitioner or hospital emergency departments. Subjects without asthma symptoms, but affected by seasonal rhinitis can experience an asthma attack. No unusual levels of air pollution were noted at the time of the epidemics, but there was a strong association with high atmospheric concentrations of pollen grains such as grasses or other allergenic plant species. However, subjects affected by pollen allergy should be informed about a possible risk of asthma attack at the beginning of a thunderstorm during pollen season.
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thunderstorm asthma and pollen allergy
Allergy, 2007Co-Authors: Gennaro Damato, G. Liccardi, Giuseppe FrenguelliAbstract:Thunderstorms have been linked to asthma epidemics, especially during the pollen seasons, and there are descriptions of asthma outbreaks associated with thunderstorms, which occurred in several cities, prevalently in Europe (Birmingham and London in the UK and Napoli in Italy) and Australia (Melbourne and Wagga Wagga). Pollen grains can be carried by thunderstorm at ground level, where pollen rupture would be increased with release of allergenic Biological Aerosols of paucimicronic size, derived from the cytoplasm and which can penetrate deep into lower airways. In other words, there is evidence that under wet conditions or during thunderstorms, pollen grains may, after rupture by osmotic shock, release into the atmosphere part of their content, including respirable, allergen-carrying cytoplasmic starch granules (0.5-2.5 microm) or other paucimicronic components that can reach lower airways inducing asthma reactions in pollinosis patients. The thunderstorm-asthma outbreaks are characterized, at the beginning of thunderstorms by a rapid increase of visits for asthma in general practitioner or hospital emergency departments. Subjects without asthma symptoms, but affected by seasonal rhinitis can experience an asthma attack. No unusual levels of air pollution were noted at the time of the epidemics, but there was a strong association with high atmospheric concentrations of pollen grains such as grasses or other allergenic plant species. However, subjects affected by pollen allergy should be informed about a possible risk of asthma attack at the beginning of a thunderstorm during pollen season.
E. Toprak - One of the best experts on this subject based on the ideXlab platform.
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Fluorescent Biological aerosol particles measured with the Waveband Integrated Bioaerosol Sensor WIBS-4: laboratory tests combined with a one year field study
Atmospheric Chemistry and Physics, 2013Co-Authors: E. Toprak, Martin SchnaiterAbstract:Abstract. In this paper bioaerosol measurements conducted with the Waveband Integrated Bioaerosol Sensor mark 4 (WIBS-4) are presented. The measurements comprise aerosol chamber characterization experiments and a one-year ambient measurement period at a semi-rural site in South Western Germany. This study aims to investigate the sensitivity of WIBS-4 to Biological and non-Biological Aerosols and detection of Biological particles in the ambient aerosol. Several types of Biological and non-Biological aerosol samples, including fungal spores, bacteria, mineral dust, ammonium sulphate, combustion soot, and fluorescent polystyrene spheres, were analyzed by WIBS-4 in the laboratory. The results confirm the sensitivity of the ultraviolet light-induced fluorescence (UV-LIF) method to Biological fluorophores and show the good discrimination capabilities of the two excitation wavelengths/detection wavebands method applied in WIBS-4. However, a weak cross-sensitivity to non-Biological fluorescent interferers remains and is discussed in this paper. All the laboratory studies have been undertaken in order to prepare WIBS-4 for ambient aerosol measurements. According to the one-year ambient aerosol study, number concentration of fluorescent Biological aerosol particles (FBAP) show strong seasonal and diurnal variability. The highest number concentration of FBAP was measured during the summer term and decreased towards the winter period when colder and drier conditions prevail. Diurnal FBAP concentrations start to increase after sunset and reach maximum values during the late night and early morning hours. On the other hand, the total aerosol number concentration was almost always higher during daytime than during nighttime and a sharp decrease after sunset was observed. There was no correlation observed between the FBAP concentration and the meteorological parameters temperature, precipitation, wind direction and wind speed. However, a clear correlation was identified between the FBAP number concentration and the relative humidity. Humidity-controlled release mechanisms of some fungal spore species are discussed as a possible explanation.
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Fluorescent Biological aerosol particles (FBAPs) measured with the Waveband Integrated Bioaerosol Sensor WIBS-4: laboratory tests combined with a one year field study
2012Co-Authors: E. Toprak, Martin SchnaiterAbstract:Abstract. In this paper bioaerosol measurements conducted with the Waveband Integrated Bioaerosol Sensor mark 4 (WIBS-4) are presented. The measurements comprise aerosol chamber characterization experiments and a one-year ambient measurement period at a semi-rural site in South Western Germany. This study aims to investigate the sensitivity of WIBS-4 to Biological and non-Biological Aerosols, performance of WIBS-4 for discrimination of several types of Aerosols, and the detection and identification of Biological particles in the ambient aerosol. Several types of Biological and non-Biological aerosol samples including spores, bacteria, pollen, mineral dust, ammonium sulphate, combustion soot, and fluorescent polystyrene spheres were analysed by WIBS-4 in the laboratory. The results confirm the sensitivity of the Ultra Violet Light Induced Fluorescence (UV-LIF) method to Biological fluorophores and show the good discrimination capabilities of the two wavelengths excitation/two wavebands detection method applied in WIBS-4. However, a weak cross-sensitivity to non-Biological fluorescent interferers remains and is discussed in this paper. All the laboratory studies have been undertaken in order to prepare WIBS-4 for ambient aerosol measurements. According to the one year ambient aerosol study, number concentration of fluorescent Biological aerosol particles (FBAP) show strong seasonal and diurnal variability. The highest number concentration of FBAP was measured during the summer term and it decreases towards the winter period when colder and drier conditions are prevailing. Diurnal FBAP concentrations start to increase after sunset and reach maximum values during the late night and early morning hours. On the other hand the total aerosol number concentration was always higher during day time than during night time and a sharp decrease after sunset was observed. There was no correlation observed between the FBAP concentration and the meteorological parameters temperature, precipitation, wind direction and wind speed. However a clear correlation was identified between the FBAP number concentration and the relative humidity. Humidity controlled release mechanisms of some fungal spore species are discussed as a possible explanation.
Yong-le Pan - One of the best experts on this subject based on the ideXlab platform.
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dual wavelength excitation single particle fluorescence spectrometer particle sorter for real time measurement of organic carbon and Biological Aerosols
Proceedings of SPIE the International Society for Optical Engineering, 2008Co-Authors: Yong-le Pan, Steven C. Hill, Ron G Pinnick, Hermes Huang, Richard K. ChangAbstract:We report the development of a Single-Particle Fluorescence Spectrometer (SPFS) system capable of measuring two UV-laser excited fluorescence spectra from a single particle on-the-fly. The two dispersed fluorescence spectra are obtained from excitation by two lasers at different wavelengths (263 nm and 351 nm). The SPFS samples single particles with sizes primarily in the 1–10 µm range. The fluorescence spectra are recorded from 280 nm to 600 nm (in 20 channels) for 263 nm excitation and from 370 nm to 700 nm (in 22 channels) for 351 nm excitation. The elastic scattering (channel 4 and 9) is also recorded for sizing each particle. A time stamp for single particles is marked with a variable time interval resolution from 10 ms to 10 minutes. The SPFS employs a virtual-impactor concentrator to concentrate respirable-sized particles with a resulting (size-dependent) effective flow rate of around 100 liters/min. The SPFS can measure single-particle spectra at a maximum rate of 90,000/sec, although the highest rates we have experienced for the ambient are only several hundred/sec. When the SPFS is combined with an aerodynamic deflector (puffer) to sort particles according to their fluorescence spectral characteristics, the SPFS/puffer system can selectively deflect and collect an enriched sample of targeted particles (at rates limited by the puffer) of 1200 particles/sec, for further examination. In laboratory tests, aerosol particles with similar UV-LIF spectra (e.g. B. subtilis and E.coli) are puffed into the reservoir of a micro-fluidic cell, where fluorescent-labeled antibodies bind to them and were classified by their labeled fluorescence. Measurements of the background ambient aerosol with the SPFS system made at sites with different regional climate (Connecticut, Maryland, and New Mexico) were clustered (unstructured hierarchical analysis) into 8-10 groups, with over 90% of all the fluorescent particles contained within these clusters (threshold dot product=0.9). However, the percentage of Aerosols in each profile differed by sampling location. The unique features and performance of the SPFS/puffer system compared to other fluorescence-based bio-aerosol sensors will be discussed, with emphasis on reduction of false alarm rates.
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single particle laser induced fluorescence spectra of Biological and other organic carbon Aerosols in the atmosphere measurements at new haven connecticut and las cruces new mexico
Journal of Geophysical Research, 2007Co-Authors: Yong-le Pan, Steven C. Hill, R G Pinnick, James M Rosen, Richard K. ChangAbstract:[1] This study focuses on organic carbon (OC) Aerosols, including natural Biological Aerosols, in the Earth's troposphere, and on laser-induced fluorescence (LIF) spectral methods for studying these Aerosols. LIF spectra of atmospheric OC and Biological Aerosols (having diameters greater than approximately 3 μm) measured at New Haven, Connecticut, and Las Cruces, New Mexico, are reported. A hierarchical clustering method was used to cluster approximately 90% of the single-particle LIF spectra into 8-10 groups. Some of these groups have spectra that are similar to spectra of some important classes of atmospheric aerosol, such as humic/fulvic acids and humic-like substances, bacteria, cellulose, marine aerosol, and polycyclic aromatic hydrocarbons (PAH). A comparison with previous measurements made at Adelphi, Maryland, reveals that the most highly populated clusters found at Adelphi, and some of the less populated ones, also appear in the LIF spectra at New Haven and Las Cruces, even though the regional climates at these locations is different (New England/Atlantic Coastal, for New Haven and Adelphi, and Chihuahuan Desert for Las Cruces), and the measurements were made in different seasons. The results are consistent with some (perhaps most) of the fluorors in OC and Biological atmospheric Aerosols being common to these three sites. On average, spectra characteristic of humic/fulvic acids and humic-like substances (HULIS) comprise 28-43% of fluorescent particles at all three sites; whereas cellulose-like spectra contribute only 1 -3%.
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Optical scattering by Biological Aerosols: experimental and computational results on spore simulants
Optics express, 2006Co-Authors: O. I. Sindoni, Yong-le Pan, Rosalba Saija, Maria Antonia Iatì, Ferdinando Borghese, Paolo Denti, Gustavo E. Fernandes, Richard K. ChangAbstract:We present both a computational and an experimental approach to the problem of Biological aerosol characterization, joining the expertises reached in the field of theoretical optical scattering by complex, arbitrary shaped particles (multipole expansion of the electromagnetic fields and Transition Matrix), and a novel experimental technique based on two-dimensional angular optical scattering (TAOS). The good agreement between experimental and computational results, together with the possibility for a laboratory single-particle angle-resolved investigation, opens a new scenario in Biological particle modelling, and might have major implications for a rapid discrimination of airborne particles.
-
Single-shot fluorescence spectra of single micron-sized particles for the characterization of Biological Aerosols
Technical Digest. Summaries of papers presented at the Conference on Lasers and Electro-Optics. Postconference Edition. CLEO '99. Conference on Lasers, 1Co-Authors: Yong-le Pan, Stephen Holler, Richard K. Chang, Steven C. Hill, Ronald G. Pinnick, S. Niles, J.r. BottigerAbstract:Summary form only given. Airborne Biological particles are minor but important component of Earth's atmosphere. They can cause disease in humans, animals, and plants. Therefore, the rapid real-time measurements of fluorescence spectra of airborne particles for the discrimination and characterization among Biological Aerosols would be useful. In this paper a new method for real-time measurement of reproducible, high signal-to-noise ratio, single-shot UV laser excited fluorescence spectra of various flowing individual Biological Aerosols is described.