Search

Primary biological aerosol (PBA) is a component of coarse mode aerosol which may affect climate and health. The possible climate impacts arise from interactions between PBA and water vapor, especially since some PBA nucleate ice at warm temperatures. The health impacts span from seasonal allergies to transmission of pathogens. Despite their potential importance, the emissions, transport, and atmospheric distribution of PBA are poorly understood, especially at high latitudes where cloud effects could be pronounced. Here we report summertime measurements of fluorescent aerosol (a proxy for PBA) over the Bering and Chukchi Seas using a Wide‐Band Integrated Bioaerosol Sensor aboard a Twin Otter, alongside a lidar which detected water column productivity. Most observations occurred at 300 m over the ocean with periodic excursions to 60 and 900 m. Loadings were always low in the marine boundary layer, despite the presence of subsurface plankton layers and in contrast to other recent reports, likely indicating low oceanic emissions during our study. Large variability was observed in PBA aloft, with higher concentrations approaching those observed over the Continental US. Back trajectory analysis showed that high loadings were associated with recent transit through the continental boundary layer and we estimate PBA emissions from the Arctic tundra of up to 300 m−2 s−1 at the warmest observed temperatures. On days with strong transport from land (∼50% of our flights), PBA accounts for 12% of supermicron number and 64% of supermicron volume, indicating potentially significant effects on the albedo, glaciation and lifetime of Arctic clouds. Plain Language Summary: Cloud cover affects Earth's temperature because clouds reflect sunlight back to space. Biological particles can cause warm clouds to freeze sooner than most other materials. This makes the clouds go away faster and reflect less sunlight. In the warming Arctic, ice, and snow (which also reflect sunlight) are melting, exposing water. Water absorbs sunlight, which makes cloud cover even more important. At the same time, Arctic ecosystems are changing, and might emit more biological particles in response. We measured biological particles over the Arctic Ocean. We found more than we were expecting and we think most of them came from land. This could change how Arctic clouds behave in important ways. As the Arctic continues to warm there might be even more of these particles in the future. Key Points: High loadings of fluorescent biological aerosol observed over the summertime Arctic, associated with remarkably warm air temperaturesBack trajectories indicate a terrestrial source for these particles with estimated emission rates comparable to those for the continental USNo evidence of biological aerosol emission from the surface ocean [ABSTRACT FROM AUTHOR]

The paper presents the results of the morphological study of aerosol particles in the urban air of Moscow (Russia) in 2019–2022 by scanning electron microscopy (SEM). Our monitoring revealed mineral and anthropogenic particles, and also primary bioaerosols (PBA), such as pollen, spores, plant fibers, etc., typical for the urban environment. Moreover, in July 2021, brochosomes, lipid secretions of semi-hard-winged insects Cicadellidae (or leafhopper), were found in several aerosol samples. They are quasi-spherical hollow porous semi-regular polyhedra (truncated icosahedra) of 0.2–0.7 microns in size, consisting mainly of carbon and oxygen. Despite the prevalence and diversity of leafhoppers, identification of their secretions in atmospheric aerosols in situ is rather rare: single articles from South Korea, Spain, the Himalayas, and the United States. In this sense, the results obtained are interesting and novel. PBA particles cover a wide size range and have a complex and diverse shape, which determines the distance and efficiency of their atmospheric transport. Pollen and fungal spores have a high allergenic potential and can have harmful effects on human health. Any new information about PBA can be useful for studying the development and dynamics of ecosystems. [ABSTRACT FROM AUTHOR]

The paper presents the results of the morphological study of aerosol particles in the urban air of Moscow (Russia) in 2019–2022 by scanning electron microscopy (SEM). Our monitoring revealed mineral and anthropogenic particles, and also primary bioaerosols (PBA), such as pollen, spores, plant fibers, etc., typical for the urban environment. Moreover, in July 2021, brochosomes, lipid secretions of semi-hard-winged insects Cicadellidae (or leafhopper), were found in several aerosol samples. They are quasi-spherical hollow porous semi-regular polyhedra (truncated icosahedra) of 0.2–0.7 microns in size, consisting mainly of carbon and oxygen. Despite the prevalence and diversity of leafhoppers, identification of their secretions in atmospheric aerosols in situ is rather rare: single articles from South Korea, Spain, the Himalayas, and the United States. In this sense, the results obtained are interesting and novel. PBA particles cover a wide size range and have a complex and diverse shape, which determines the distance and efficiency of their atmospheric transport. Pollen and fungal spores have a high allergenic potential and can have harmful effects on human health. Any new information about PBA can be useful for studying the development and dynamics of ecosystems.

Abstract In this work, we present on-line fluorescent aerosol measurements by the wideband integrated bioaerosol spectrometer (WIBS-4A) near an industrial zone in Nanjing, a megacity in the Yangtze-River-Delta (YRD) region. The fieldwork was conducted from April 1 to May 8, 2014. A TSI. 3321 aerosol-particle-sizer (APS) was simultaneously deployed to measure the total number size distribution of aerosol with diameter from 0.8–20 μm. Both WIBS-4A and APS reported similar number concentration and temporal profiles (R2 = 0.72). However, the daily average number of potential bioaerosols was only 0.5 ± 0.2% of the total particles detected by the WIBS-4A and displayed a completely different diurnal profile from that of APS. In addition, WIBS-4A can only provide integrated fluorescent signals, which strongly limited the potential to specifically identify the bioaerosols. Accordingly, hierarchical-agglomerative-cluster-analysis (HACA) was utilized to identify and speciate the potential bioaerosols from the WIBS-4A dataset. By maximizing the total distances among all potential cluster centers, a 12-cluster solution was accepted as the optimum result. These clusters were further identified according to their fluorescent signatures, size, and morphology, i.e., non-bioaerosols, bacteria, and fungal spores and/or pollen fragments. Bacteria were the dominant bioaerosol species detected in this work. The diurnal profiles of bioaerosols correlated very well with relatively humidity (RH), reaching daily maxima around 3 AM~6 AM, indicating the presence of humidity controlled bioaerosol emission mechanism, i.e., bacteria may flourish under moderate ambient temperature, RH, and the absence of UV radiation. The size- and AF-distributions of bioaerosols indicated that bioaerosols normally varied substantially in size and assumed a rather irregular shape. Although the number concentration of bioaerosols was relatively small, most bioaerosols can efficiently serve as ice nuclei by providing rough and irregular surfaces, verified by the observation results. Therefore, WIBS-4A measurements can still be informative for investigations of bioaerosols in the atmosphere, especially when HACA method was incorporated into the data processing. Graphical abstract Unlabelled Image Highlights • Bioaerosols only accounted for <1% of the total WIBS-4A signals. • WIBS-4A combined with cluster analysis may be an effective way to identify bioaerosols. • Bacteria, fungal spores and/or pollen fragments were the dominant bioaerosols in Nanjing. • Bioaerosols may present complex size-distributions and morphology. [ABSTRACT FROM AUTHOR]

To investigate the contribution of primary biological aerosol particles (PBAPs) to aerosol and the correlations with brown carbon (BrC) light absorption over the Tibetan Plateau (TP), the total suspended particle (TSP) samples were collected at three high altitude sites. The spatial variations of PBAPs tracers and absorption Ångström exponent (AAE) were obtained over the TP for the first time. Elevated PBAPs tracers concentrations were observed in the northeastern and southwestern sites compared to the central TP. The high concentrations of FSPD OC (the fungal-spore-derived OC and plant-debris OC) and PBAPs were obtained in the northeastern (with 74 ng m−3 and 2333 ng m−3) and southwestern sites (with 80 ng m−3 and 2682 ng m−3), respectively. The results indicated that PBAPs may be important fraction of BrC chromophores in the southwestern TP. The highest AAEs of BrC, primary BrC (BrC pri), and secondary BrC (BrC sec) were observed in the northeastern site with the values of 5.1, 3.7, and 5.7, respectively. The potential PBAPs and FSPD OC source distributions were obtained. The results are important for evaluating the effects of PBAPs in the TP. [Display omitted] • The spatial variations of primary biogenic contribution and AAE of brown carbon were investigated. • The heighten concentrations of FSPD OC and PBAPs were obtained in the northeastern and southwestern sites, respectively. • The potential PBAPs and FSPD OC source distributions were obtained. [ABSTRACT FROM AUTHOR]

This study investigates the hygroscopic growth of pollen. An electrodynamic balance was used to measure the water uptake on pollen and an environmental scanning electron microscope was used to visualize the response of the pollen to subsaturated humidities. Pollen was found to be moderately hygroscopic and its surface wettable at high humidities. The hygroscopicity data were parameterized using κ-Köhler theory and used in a rising parcel cloud model to investigate the effect of pollen on sulfate activation. Our data suggest that extreme pollen concentrations (>1000 m−3) may interfere with the activation of the background sulphate aerosol mode in pristine environments. Copyright © 2012 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

Abstract: Although bacteria are ubiquitous in the near-surface atmosphere, the temporal dynamics of airborne bacterial communities have not been well-studied. We examined seasonal shifts in bacterial abundances, the relative contribution of bacteria to total aerosol loads, and bacterial community structure at a high-elevation research station in northern Colorado, USA. Aerosol samples were collected from the near-surface atmosphere over 5–10 days during each of the four calendar seasons. Bacterial abundances varied by season with the highest concentrations observed during the fall and spring seasons, consistent with the changes in total particle concentrations, with bacterial cells often representing a large fraction (22% on average) of the total near-surface aerosol particles >0.5 μm. Bacterial community composition, determined via barcoded pyrosequencing, also varied significantly by season. The dominant taxa in the spring, winter, and second half of the fall sampling periods (when the ground was snow covered) were bacterial taxa commonly found in other cold environments while the summer and first half of the fall samples contained taxa that were likely derived from soil and leaf-surface environments. Bacteria are clearly an important component of atmospheric aerosols with the abundance and composition of these airborne bacterial communities shaped by seasonal shifts in atmospheric conditions and the conditions of the local terrestrial environment. [Copyright &y& Elsevier]