scholarly journals Intercomparison of Multiple UV-LIF Spectrometers Using the Aerosol Challenge Simulator

Atmosphere ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 797 ◽  
Author(s):  
Elizabeth Forde ◽  
Martin Gallagher ◽  
Maurice Walker ◽  
Virginia Foot ◽  
Alexis Attwood ◽  
...  
Keyword(s):  
Ultraviolet Light ◽  
Fluorescence Intensity ◽  
Biological Samples ◽  
Aerosol Particles ◽  
Science And Technology ◽  
Laboratory Studies ◽  
Biological Particles ◽  
Fluorescent Particles ◽  
Biological Particle ◽  
Biological Aerosol Particles

Measurements of primary biological aerosol particles (PBAPs) have been conducted worldwide using ultraviolet light-induced fluorescence (UV-LIF) spectrometers. However, how these instruments detect and respond to known biological and non-biological particles, and how they compare, remains uncertain due to limited laboratory intercomparisons. Using the Defence Science and Technology Laboratory, Aerosol Challenge Simulator (ACS), controlled concentrations of biological and non-biological aerosol particles, singly or as mixtures, were produced for testing and intercomparison of multiple versions of the Wideband Integrated Bioaerosol Spectrometer (WIBS) and Multiparameter Bioaerosol Spectrometer (MBS). Although the results suggest some challenges in discriminating biological particle types across different versions of the same UV-LIF instrument, a difference in fluorescence intensity between the non-biological and biological samples could be identified for most instruments. While lower concentrations of fluorescent particles were detected by the MBS, the MBS demonstrates the potential to discriminate between pollen and other biological particles. This study presents the first published technical summary and use of the ACS for instrument intercomparisons. Within this work a clear overview of the data pre-processing is also presented, and documentation of instrument version/model numbers is suggested to assess potential instrument variations between different versions of the same instrument. Further laboratory studies sampling different particle types are suggested before use in quantifying impact on ambient classification.

scholarly journals Size distributions and temporal variations of biological aerosol particles in the Amazon rainforest characterized by microscopy and real-time UV-APS fluorescence techniques during AMAZE-08

2012 ◽  
Vol 12 (24) ◽  
pp. 11997-12019 ◽  
Author(s):  
J. A. Huffman ◽  
B. Sinha ◽  
R. M. Garland ◽  
A. Snee-Pollmann ◽  
S. S. Gunthe ◽  
...  
Keyword(s):  
Real Time ◽  
Inorganic Material ◽  
Aerosol Particles ◽  
Fungal Spores ◽  
Dust Particles ◽  
Laser Induce Fluorescence ◽  
Biological Origin ◽  
Biological Particles ◽  
Total Particle ◽  
Biological Aerosol Particles

Abstract. As a part of the AMAZE-08 campaign during the wet season in the rainforest of central Amazonia, an ultraviolet aerodynamic particle sizer (UV-APS) was operated for continuous measurements of fluorescent biological aerosol particles (FBAP). In the coarse particle size range (> 1 μm) the campaign median and quartiles of FBAP number and mass concentration were 7.3 × 104 m−3 (4.0–13.2 × 104 m−3) and 0.72 μg m−3 (0.42–1.19 μg m−3), respectively, accounting for 24% (11–41%) of total particle number and 47% (25–65%) of total particle mass. During the five-week campaign in February–March 2008 the concentration of coarse-mode Saharan dust particles was highly variable. In contrast, FBAP concentrations remained fairly constant over the course of weeks and had a consistent daily pattern, peaking several hours before sunrise, suggesting observed FBAP was dominated by nocturnal spore emission. This conclusion was supported by the consistent FBAP number size distribution peaking at 2.3 μm, also attributed to fungal spores and mixed biological particles by scanning electron microscopy (SEM), light microscopy and biochemical staining. A second primary biological aerosol particle (PBAP) mode between 0.5 and 1.0 μm was also observed by SEM, but exhibited little fluorescence and no true fungal staining. This mode may have consisted of single bacterial cells, brochosomes, various fragments of biological material, and small Chromalveolata (Chromista) spores. Particles liquid-coated with mixed organic-inorganic material constituted a large fraction of observations, and these coatings contained salts likely from primary biological origin. We provide key support for the suggestion that real-time laser-induce fluorescence (LIF) techniques using 355 nm excitation provide size-resolved concentrations of FBAP as a lower limit for the atmospheric abundance of biological particles in a pristine environment. We also show some limitations of using the instrument for ambient monitoring of weakly fluorescent particles < 2 μm. Our measurements confirm that primary biological particles, fungal spores in particular, are an important fraction of supermicron aerosol in the Amazon and that may contribute significantly to hydrological cycling, especially when coated by mixed inorganic material.

scholarly journals Abundance of fluorescent biological aerosol particles at temperatures conducive to the formation of mixed-phase and cirrus clouds

2016 ◽  
Author(s):  
Cynthia H. Twohy ◽  
Gavin R. McMeeking ◽  
Paul J. DeMott ◽  
Christina S. McCluskey ◽  
Thomas C. J. Hill ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Climate Model ◽  
Aerosol Particles ◽  
Fungal Spores ◽  
Mixed Phase ◽  
Free Troposphere ◽  
Biological Particles ◽  
New Instrument ◽  
Vertical Distributions ◽  
Biological Aerosol Particles

Abstract. Some types of biological particles are known to nucleate ice at warmer temperatures than mineral dust, with the potential to influence cloud microphysical properties and climate. However, the prevalence of these particle types above the atmospheric boundary layer is not well known. Many types of biological particles fluoresce when exposed to ultraviolet light, and the Wideband Integrated Bioaerosol Sensor takes advantage of this characteristic to perform real-time measurements of fluorescent biological aerosol particles (FBAP). This relatively new instrument was flown on the National Center for Atmospheric Research Gulfstream-V aircraft to measure concentrations of fluorescent biological particles from different potential sources and at various altitudes over the U. S. western plains states in early autumn. Clear-air number concentrations of FBAP larger than 0.8 µm diameter usually decreased with height, and generally were about 10–100 L−1 in the continental boundary layer, but were always much lower at temperatures colder than 255 K in the free troposphere. At intermediate temperatures where biological ice nucleating particles may influence mixed-phase cloud formation (255 K ≤ T ≤ 270 K), concentrations of fluorescent particles were the most variable, and were occasionally near boundary layer concentrations. Predicted vertical distributions of ice nucleating particle concentrations based on FBAP measurements in this temperature regime sometimes reached typical concentrations of primary ice in clouds, but were often much lower. If convection was assumed to lift boundary layer FBAP particles without losses to the free troposphere, better agreement between predicted ice-nucleating particle concentrations and typical ice crystal concentrations was achieved. Ice nucleating particle concentrations were also measured during one flight and showed a decrease with height, and concentrations were consistent with a relationship to FBAP established previously at the forested surface site below. The vertical distributions of FBAP measured on five flights were also compared with those for bacteria, fungal spores and pollen predicted from the EMAC global chemistry-climate model for the same geographic region.

scholarly journals Abundance of fluorescent biological aerosol particles at temperatures conducive to the formation of mixed-phase and cirrus clouds

2016 ◽  
Vol 16 (13) ◽  
pp. 8205-8225 ◽  
Author(s):  
Cynthia H. Twohy ◽  
Gavin R. McMeeking ◽  
Paul J. DeMott ◽  
Christina S. McCluskey ◽  
Thomas C. J. Hill ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Climate Model ◽  
Aerosol Particles ◽  
Fungal Spores ◽  
Mixed Phase ◽  
Free Troposphere ◽  
Spores And Pollen ◽  
Biological Particles ◽  
Vertical Distributions ◽  
Biological Aerosol Particles

Abstract. Some types of biological particles are known to nucleate ice at warmer temperatures than mineral dust, with the potential to influence cloud microphysical properties and climate. However, the prevalence of these particle types above the atmospheric boundary layer is not well known. Many types of biological particles fluoresce when exposed to ultraviolet light, and the Wideband Integrated Bioaerosol Sensor takes advantage of this characteristic to perform real-time measurements of fluorescent biological aerosol particles (FBAPs). This instrument was flown on the National Center for Atmospheric Research Gulfstream V aircraft to measure concentrations of fluorescent biological particles from different potential sources and at various altitudes over the US western plains in early autumn. Clear-air number concentrations of FBAPs between 0.8 and 12 µm diameter usually decreased with height and generally were about 10–100 L−1 in the continental boundary layer but always much lower at temperatures colder than 255 K in the free troposphere. At intermediate temperatures where biological ice-nucleating particles may influence mixed-phase cloud formation (255 K  ≤ T ≤  270 K), concentrations of fluorescent particles were the most variable and were occasionally near boundary-layer concentrations. Predicted vertical distributions of ice-nucleating particle concentrations based on FBAP measurements in this temperature regime sometimes reached typical concentrations of primary ice in clouds but were often much lower. If convection was assumed to lift boundary-layer FBAPs without losses to the free troposphere, better agreement between predicted ice-nucleating particle concentrations and typical ice crystal concentrations was achieved. Ice-nucleating particle concentrations were also measured during one flight and showed a decrease with height, and concentrations were consistent with a relationship to FBAPs established previously at the forested surface site below. The vertical distributions of FBAPs measured on five flights were also compared with those for bacteria, fungal spores, and pollen predicted from the EMAC global chemistry–climate model for the same geographic region.

scholarly journals Fluorescent biological aerosol particles: Concentrations, emissions, and exposures in a northern California residence

Indoor Air ◽  
2018 ◽  
Vol 28 (4) ◽  
pp. 559-571 ◽  
Author(s):  
Y. Tian ◽  
Y. Liu ◽  
P. K. Misztal ◽  
J. Xiong ◽  
C. M. Arata ◽  
...  
Keyword(s):  
Aerosol Particles ◽  
Northern California ◽  
Biological Aerosol Particles

scholarly journals Characterisation of biofluorescent aerosol emissions over winter and summer periods in the United Kingdom

2018 ◽  
Author(s):  
Elizabeth Forde ◽  
Martin Gallagher ◽  
Virginia Foot ◽  
Roland Sarda-Esteve ◽  
Ian Crawford ◽  
...  
Keyword(s):  
United Kingdom ◽  
Relative Humidity ◽  
Aerosol Particles ◽  
Fungal Spores ◽  
Ultra Violet ◽  
Fungal Spore ◽  
Complete Analysis ◽  
Hierarchical Agglomerative Cluster ◽  
The United Kingdom ◽  
Fluorescent Particles

Abstract. Primary biological aerosol particles (PBAP) are an abundant subset of atmospheric aerosol particles which comprise viruses, bacteria, fungal spores, pollen, and fragments such as plant and animal debris. The abundance and diversity of these particles remain poorly constrained, causing significant uncertainties for modelling scenarios and for understanding the potential implications of these particles in different environments. PBAP concentrations were studied at four different sites in the United Kingdom (Weybourne, Davidstow, Capel Dewi, and Chilbolton) using an ultra-violet light induced fluorescence (UV-LIF) instrument, the Wideband Integrated Bioaerosol Spectrometer (WIBS), versions 3 and 4. Using hierarchical agglomerative cluster (HAC) analysis, particles were statistically discriminated between. Fluorescent particles and clusters were then analysed by assessing their diurnal variation and their relationship to the meteorological variables, temperature and relative humidity, and wind speed and direction. Using local land cover types, sources of the suspected fluorescent particles and clusters were then identified. Most sites exhibited a wet discharged fungal spore dominance, with the exception of one site, Davidstow, which had higher concentrations of bacteria, suggested to result from the presence of a local dairy factory. Differences were identified as to the sources of wet discharged fungal spores, with particles originating from arable and horticultural land at Chilbolton, and improved grassland areas at Weybourne. Total fluorescent particles at Capel Dewi were inferred to comprise two sources, with bacteria originating from the broadleaf and coniferous woodland and wet discharged fungal spores from nearby improved grassland areas, similar to Weybourne. The use of HAC and a higher fluorescence threshold (9SD) produced clusters which were considered to be biological following the complete analysis. More knowledge of the reaction of speciated biological particles to differences in meteorology, such as relative humidity and temperature would aid characterisation studies such as this.

scholarly journals Simulating the influence of primary biological aerosol particles on clouds by heterogeneous ice nucleation

2018 ◽  
Vol 18 (20) ◽  
pp. 15437-15450 ◽  
Author(s):  
Matthias Hummel ◽  
Corinna Hoose ◽  
Bernhard Pummer ◽  
Caroline Schaupp ◽  
Janine Fröhlich-Nowoisky ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Aerosol Particles ◽  
Fungal Spores ◽  
Ice Nucleation ◽  
Ice Crystals ◽  
Atmospheric Measurements ◽  
Cloud Ice ◽  
Biological Aerosol Particles ◽  
Ice Phase ◽  
Heterogeneous Ice Nucleation

Abstract. Primary ice formation, which is an important process for mixed-phase clouds with an impact on their lifetime, radiative balance, and hence the climate, strongly depends on the availability of ice-nucleating particles (INPs). Supercooled droplets within these clouds remain liquid until an INP immersed in or colliding with the droplet reaches its activation temperature. Only a few aerosol particles are acting as INPs and the freezing efficiency varies among them. Thus, the fraction of supercooled water in the cloud depends on the specific properties and concentrations of the INPs. Primary biological aerosol particles (PBAPs) have been identified as very efficient INPs at high subzero temperatures, but their very low atmospheric concentrations make it difficult to quantify their impact on clouds. Here we use the regional atmospheric model COSMO–ART to simulate the heterogeneous ice nucleation by PBAPs during a 1-week case study on a domain covering Europe. We focus on three highly ice-nucleation-active PBAP species, Pseudomonas syringae bacteria cells and spores from the fungi Cladosporium sp. and Mortierella alpina. PBAP emissions are parameterized in order to represent the entirety of bacteria and fungal spores in the atmosphere. Thus, only parts of the simulated PBAPs are assumed to act as INPs. The ice nucleation parameterizations are specific for the three selected species and are based on a deterministic approach. The PBAP concentrations simulated in this study are within the range of previously reported results from other modeling studies and atmospheric measurements. Two regimes of PBAP INP concentrations are identified: a temperature-limited and a PBAP-limited regime, which occur at temperatures above and below a maximal concentration at around −10 ∘C, respectively. In an ensemble of control and disturbed simulations, the change in the average ice crystal concentration by biological INPs is not statistically significant, suggesting that PBAPs have no significant influence on the average state of the cloud ice phase. However, if the cloud top temperature is below −15 ∘C, PBAP can influence the cloud ice phase and produce ice crystals in the absence of other INPs. Nevertheless, the number of produced ice crystals is very low and it has no influence on the modeled number of cloud droplets and hence the cloud structure.

scholarly journals It’s Important to Go to the Laboratory: Malte Ziewitz Talks with Michael Lynch

2018 ◽  
Vol 4 ◽  
pp. 366 ◽  
Author(s):  
Malte Ziewitz ◽  
Michael Lynch
Keyword(s):  
Social Studies ◽  
Science And Technology Studies ◽  
Blow Up ◽  
Science And Technology ◽  
Laboratory Studies ◽  
Technology Studies ◽  
Social Studies Of Science ◽  
Origin Stories

Why would anyone still want to go to the laboratory in 2018? In this interview, Michael Lynch answers this and other questions, reflecting on his own journey in, through, and alongside the field of science and technology studies (STS). Starting from his days as a student of Harold Garfinkel’s at UCLA to more recent times as editor of Social Studies of Science, Lynch talks about the rise of origin stories in the field; the role of ethnomethodology in his thinking; the early days of laboratory studies; why “turns” and “waves” might better be called “spins”; what he learned from David Edge; why we should be skeptical of the presumption that STS enhances the democratization of science; and why it might be time to “blow up STS”––an appealing idea that Malte Ziewitz takes up in his reflection following the interview.

scholarly journals Ice nucleating particles at a coastal marine boundary layer site: correlations with aerosol type and meteorological conditions

2015 ◽  
Vol 15 (12) ◽  
pp. 16273-16323 ◽  
Author(s):  
R. H. Mason ◽  
M. Si ◽  
J. Li ◽  
C. Chou ◽  
R. Dickie ◽  
...  
Keyword(s):  
Size Distribution ◽  
Marine Boundary Layer ◽  
Aerosol Particles ◽  
Meteorological Conditions ◽  
Marine Aerosols ◽  
Coastal Site ◽  
Carbon Particles ◽  
Biological Particles ◽  
Ice Nuclei ◽  
Coastal Marine

Abstract. Information on what aerosol particle types are the major sources of ice nucleating particles (INPs) in the atmosphere is needed for climate predictions. To determine which aerosol particles are the major sources of immersion-mode INPs at a coastal site in Western Canada, we investigated correlations between INP number concentrations and both concentrations of different atmospheric particles and meteorological conditions. We show that INP number concentrations are strongly correlated with the number concentrations of fluorescent bioparticles between −15 and −25 °C, and that the size distribution of INPs is most consistent with the size distribution of fluorescent bioparticles. We conclude that biological particles were likely the major source of ice nuclei at freezing temperatures between −15 and −25 °C at this site for the time period studied. At −30 °C, INP number concentrations are also well correlated with number concentrations of the total aerosol particles ≥ 0.5 μm, suggesting that non-biological particles may have an important contribution to the population of INPs active at this temperature. As we found that black carbon particles were unlikely to be a major source of ice nuclei during this study, these non-biological INPs may include mineral dust. Furthermore, correlations involving tracers of marine aerosols and marine biological activity indicate that the majority of INPs measured at the coastal site likely originated from terrestrial rather than marine sources. Finally, six existing empirical parameterizations of ice nucleation were tested to determine if they accurately predict the measured INP number concentrations. We found that none of the parameterizations selected are capable of predicting INP number concentrations with high accuracy over the entire temperature range investigated.

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