Abstract. Atmospheric particles of biological origin, also referred to as bioaerosols or primary biological aerosol particles (PBAP), are important to various human health and environmental systems. There has been a recent steep increase in the frequency of published studies utilizing commercial instrumentation based on ultraviolet laser/light-induced fluorescence (UV-LIF), such as the WIBS (wideband integrated bioaerosol sensor) or UV-APS (ultraviolet aerodynamic particle sizer), for bioaerosol detection both outdoors and in the built environment. Significant work over several decades supported the development of the general technologies, but efforts to systematically characterize the operation of new commercial sensors have remained lacking. Specifically, there have been gaps in the understanding of how different classes of biological and non-biological particles can influence the detection ability of LIF instrumentation. Here we present a systematic characterization of the WIBS-4A instrument using 69 types of aerosol materials, including a representative list of pollen, fungal spores, and bacteria as well as the most important groups of non-biological materials reported to exhibit interfering fluorescent properties. Broad separation can be seen between the biological and non-biological particles directly using the five WIBS output parameters and by taking advantage of the particle classification analysis introduced by Perring et al. (2015). We highlight the importance that particle size plays on observed fluorescence properties and thus in the Perring-style particle classification. We also discuss several particle analysis strategies, including the commonly used fluorescence threshold defined as the mean instrument background (forced trigger; FT) plus 3 standard deviations (σ ) of the measurement. Changing the particle fluorescence threshold was shown to have a significant impact on fluorescence fraction and particle type classification. We conclude that raising the fluorescence threshold from FT + 3σ to FT + 9σ does little to reduce the relative fraction of biological material considered fluorescent but can significantly reduce the interference from mineral dust and other non-biological aerosols. We discuss examples of highly fluorescent interfering particles, such as brown carbon, diesel soot, and cotton fibers, and how these may impact WIBS analysis and data interpretation in various indoor and outdoor environments. The performance of the particle asymmetry factor (AF) reported by the instrument was assessed across particle types as a function of particle size, and comments on the reliability of this parameter are given. A comprehensive online supplement is provided, which includes size distributions broken down by fluorescent particle type for all 69 aerosol materials and comparing threshold strategies. Lastly, the study was designed to propose analysis strategies that may be useful to the broader community of UV-LIF instrumentation users in order to promote deeper discussions about how best to continue i...

Abstract. Atmospheric particles of biological origin, also referred to as bioaerosols or primary biological aerosol particles (PBAP), are important to various human health and environmental systems. There has been a recent steep increase in the frequency of published studies utilizing commercial instrumentation based on ultraviolet laser/light-induced fluorescence (UV-LIF), such as the WIBS (wideband integrated bioaerosol sensor) or UV-APS (ultraviolet aerodynamic particle sizer), for bioaerosol detection both outdoors and in the built environment. Significant work over several decades supported the development of the general technologies, but efforts to systematically characterize the operation of new commercial sensors has remained lacking. Specifically, there have been gaps in the understanding of how different classes of biological and non-biological particles can influence the detection ability of LIF-instrumentation. Here we present a systematic characterization of the WIBS-4A instrument using 69 types of aerosol materials, including a representative list of pollen, fungal spores, and bacteria as well as the most important groups of non-biological materials reported to exhibit interfering fluorescent properties. Broad separation can be seen between the biological and non-biological particles directly using the five WIBS output parameters and by taking advantage of the particle classification analysis introduced by Perring et al. (2015). We highlight the importance that particle size plays on observed fluorescence properties and thus in the Perring-style particle classification. We also discuss several particle analysis strategies, including the commonly used fluorescence threshold defined as the mean instrument background (forced trigger; FT) plus 3 standard deviations (σ) of the measurement. Changing the particle fluorescence threshold was shown to have a significant impact on fluorescence fraction and particle type classification. We conclude that raising the fluorescence threshold from FT + 3σ to FT + 9σ does little to reduce the relative fraction of biological material considered fluorescent, but can significantly reduce the interference from mineral dust and other non-biological aerosols. We discuss examples of highly fluorescent interfering particles, such as brown carbon, diesel soot, and cotton fibers, and how these may impact WIBS analysis and data interpretation in various indoor and outdoor environments. A comprehensive online supplement is provided, which includes size distributions broken down by fluorescent particle type for all 69 aerosol materials and comparing two threshold strategies. Lastly, the study was designed to propose analysis strategies that may be useful to the broader community of UV-LIF instrumentation users in order to promote deeper discussions about how best to continue improving UV-LIF instrumentation and analysis strategies.

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The increasing prevalence and use of nanotechnology-enabled consumer products have increased potential consumer exposures to nanoparticles; however, there is still a lack of data characterizing such consumer exposure. The research reported here investigated near-field airborne exposures due to the use of 13 silver (Ag)-based and 5 zinc (Zn)-based consumer sprays. The products were sprayed into a specially designed glove box, and all products were applied with equal spraying duration and frequency. Size distribution and concentration of the released particles were assessed using a Scanning Mobility Particle Sizer and an Aerodynamic Particle Sizer. Inductively coupled plasma mass spectrometry (ICP-MS) was used to investigate the presence of metals in all investigated products. Spray liquids and airborne particles from select products were examined using transmission electron microscopy (TEM) and Energy Dispersive X-ray Spectroscopy (EDS). We found that all sprays produced airborne particles ranging in size from nano-sized particles (<100 nm) to coarse particles (>2.5 µm); however, there was a substantial variation in the released particle concentration depending on a product. The total aerosol mass concentration was dominated by the presence of coarse particles, and it ranged from ~30 µg/m 3 to ~30,000 µg/m 3 . The TEM verified the presence of nanoparticles and their agglomerates in liquid and airborne states. The products were found to contain not only Ag and Zn compounds -as advertised on the product labeling -but also a variety of other metals including lithium, strontium, barium, lead, manganese and others. The results presented here can be used as input to model population exposures as well as form a basis for human health effects studies due to the use nanotechnology-enabled products.

Background Recently, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission through exposure to aerosols has been suggested. Therefore, we investigated the possibility of aerosol SARS-CoV-2 transmission within an apartment complex where residents reported testing positive for SARS-CoV-2 despite having no direct contact with other SARS-CoV-2–infected people. Methods Information on symptom onset and exposure history of the patients was collected by global positioning system (GPS) tracking to investigate possible points of contact or spread. Samples collected from patients and from various areas of the complex were analyzed using RNA sequencing. Phylogenetic analysis was also performed. Results Of 19 people with confirmed SARS-CoV-2 infection, 5 reported no direct contact with other residents and were from apartments in the same vertical line. Eight environmental samples tested positive for the virus. Phylogenetic analyses revealed that 3 of the positive cases and 1 environmental sample belonged to the B.1.497 lineage. Additionally, 3 clinical specimens and 1 environmental sample from each floor of the complex had the same amino acid substitution in the ORF1ab region. Conclusions SARS-CoV-2 transmission possibly occurs between different floors of an apartment building through aerosol transmission via nonfunctioning drain traps.

Our study indicates that CGA and CP extracts prevented depressive behavior and thereby have potential as natural antidepressants.

Here, we present a concept of a personal electrostatic bioaerosol sampler (PEBS), which is an open channel collector consisting of a novel wire-to-wire particle charger and a collection section housing a double-sided and removable metal collection plate and two quarter-cylinder ground electrodes. The charger consists of a tungsten wire (25.4 mm long and 0.076 mm in diameter) connected to high voltage and positioned in the center of the charging section (a cylinder 50.8 mm long and 25.4 mm in diameter); a ring of stainless steel wire 0.381 mm in diameter surrounds the hot electrode at its midpoint and is grounded. The newly designed wire-to-wire charger produces lower ozone concentrations compared to traditional wire-to-plate or wire-to-cylinder charger designs. The particles captured on the collection plate are easily eluted using water or other fluids. The sampler was iteratively optimized for optimum charging and collection voltages, and collection electrode geometry. When tested with polystyrene latex particles ranging from 0.026 mm to 3.1 mm in diameter and 10 L/min collection flow rate, the sampler's collection efficiency was approximately 70%-80% at charging and collection voltages of C5.5 kV and ¡7 kV, respectively. The PEBS showed this collection efficiency at sampling times ranging from 10 min to 4 h. Preliminary tests with Bacillus atrophaeus bacterial cells and fungal spores of Penicillium chrysogenum showed similar collection efficiency. The use of a unique wire-to-wire charger resulted in ozone production below 10 ppb. Due to low ozone emissions, this sampler will allow maintaining desirable physiological characteristics of the collected bioaerosols, leading to a more accurate sample analysis.

Background: Magnolia officinalis Rehder and EH Wilson (M. officinalis) are traditional Chinese medicines widely used for gastrointestinal (GI) tract motility disorder in Asian countries. We investigated the effects of an ethanol extract of M. officinalis (MOE) on the pacemaker potentials of cultured interstitial cells of Cajal (ICCs) in vitro and its effects on GI motor functions in vivo. Methods: We isolated ICCs from small intestines, and the whole-cell patch-clamp configuration was used to record the pacemaker potentials in cultured ICCs in vitro. Both gastric emptying (GE) and intestinal transit rates (ITRs) were investigated in normal and GI motility dysfunction (GMD) mice models in vivo. Results: MOE depolarized ICC pacemaker potentials dose-dependently. Pretreatment with methoctramine (a muscarinic M₂ receptor antagonist) and 4-DAMP (a muscarinic M₃ receptor antagonist) inhibited the effects of MOE on the pacemaker potential relative to treatment with MOE alone. In addition, MOE depolarized pacemaker potentials after pretreatment with Y25130 (a 5-HT₃ receptor antagonist), GR113808 (a 5-HT₄ receptor antagonist) or SB269970 (a 5-HT₇ receptor antagonist). However, pretreatment with RS39604 (a 5-HT₄ receptor antagonist) blocked MOE-induced pacemaker potential depolarizations. Intracellular GDPβS inhibited MOE-induced pacemaker potential depolarization, as did pretreatment with Ca²⁺ free solution or thapsigargin. In normal mice, the GE and ITR values were significantly and dose-dependently increased by MOE. In loperamide-and cisplatin-induced GE delay models, MOE administration reversed the GE deficits. The ITRs of the GMD mice were significantly reduced relative to those of normal mice, which were significantly and dose-dependently reversed by MOE. Conclusion: These results suggest that MOE dose-dependently depolarizes ICCs pacemaker potentials through M₂ and M₃ receptors via internal and external Ca²⁺ regulation through G protein pathways in vitro. Moreover, MOE increased GE and ITRs in vivo in normal and GMD mouse models. Taken together, the results of this study show that MOE have the potential for development as a gastroprokinetic agent in GI motility function.