Aerosols of biological origin play a vital role in the Earth system, particularly in the interactions between atmosphere, biosphere, climate, and public health. Airborne bacteria, fungal spores, pollen, and other bioparticles are essential for the reproduction and spread of organisms across various ecosystems, and they can cause or enhance human, animal, and plant diseases. Moreover, they can serve as nuclei for cloud droplets, ice crystals, and precipitation, thus influencing the hydrological cycle and climate. The sources, abundance, composition, and effects of biological aerosols and the atmospheric microbiome are, however, not yet well characterized and constitute a large gap in the scientific understanding of the interaction and co-evolution of life and climate in the Earth system. This review presents an overview of the state of bioaerosol research, highlights recent advances, and outlines future perspectives in terms of bioaerosol identification, characterization, transport, and transformation processes, as well as their interactions with climate, health, and ecosystems, focusing on the role bioaerosols play in the Earth system. © 2016 The Authors

Sachin S. Gunthe

Department Of Civil Engineering

Allergens

Atmospheric aerosols

Bacteria

Fungi

Health

Precipitation (meteorology)

AIRBORNE BACTERIA

Bioaerosols

BIOLOGICAL AEROSOL

CLOUD DROPLETS

Future perspectives

HYDROLOGICAL CYCLES

ICE NUCLEI

Transformation process

Ecosystems

aerosol

ALLERGY

ATMOSPHERE-BIOSPHERE INTERACTION

bacterium

CLIMATE CONDITIONS

Fungus

ICE CRYSTAL

Public Health

Animalia

Fulltext

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Atmospheric Research

This study provides baseline information about indoor-outdoor PM concentrations, size-resolved bioaerosol concentration, size distribution and diversity, I/O ratios of PM and bioaerosol, indoor bioaerosol emissions for five locations such as laboratory, students’ office, air-conditioned room, eatery, and residence. While most of the indoor air quality studies reported so far emphasized on a distinct type of indoor environment at a time, this study provides a first-hand account about PM and bioaerosols simultaneously measured and compared from diverse yet commonly encountered indoor locations of southern Indian region. PM2.5 and PM10 was found to have similar concentration distributions at all locations. Elevated cooking activity and human induced floor resuspensions led to the highest indoor-outdoor number concentration of PM at eatery. The I/O mass concentration ratios indicated the influence of outdoor PM on indoor environment of laboratory. Presence of distinct sources that contributed to significant PM mass variations at indoor and outdoor environments were substantiated with ANOVA and chi-square test results. Human occupancy and potted plants was found contributing to the elevated indoor bacterial concentrations (&gt;800 CFU m−3). Fine to coarse bioaerosol fractions implied the abundant presence of coarse mode bacteria and fungi amounting to &gt;80% of total cultivable bioaerosol load across all locations. Bacilli and Gammaproteobacteria dominated the bacterial aerosols while Cladosporium and Aspergillus dominated the fungal aerosols. Fungi contributed highest to the mass fraction of PM10 in comparison to bacteria, both indoor and outdoor. Highest bacterial emission rates were observed at air-conditioned room (4.85 × 105 CFU/h/person) and fungal emissions at laboratory (4.60 × 105 CFU/h/person). © 2018 Elsevier Ltd

Building and Environment

Assessment of PM and bioaerosols at diverse indoor environments in a southern tropical Indian region

Bioaerosols abundantly found in the atmosphere can potentially influence the climate by acting as ice nuclei and thus profoundly influencing the hydrological cycle. As the first attempt over India, we report the diversity, abundance, and ice nucleating ability of bacteria present in the rainwater collected at Chennai, during summer and two contrasting monsoon seasons. Diverse bacterial communities were present in all the twenty rainwater samples and predominantly belonged to Actinobacteria (6%), Alpha proteobacter (9%), Bacilli (29%), Betaproterobacteria (14%), Flavobacteria (3%), and Gammaproteobacteria (39%). The most efficient ice nucleating bacteria such as Pseudomonas sp. and Pantoea sp. were present in our precipitation samples and they contributed to 8.4% and 9.4% of the total cultivable bacterial species obtained. The relative abundance of Pseudomonas was highest during the south-west monsoon (75%) whereas Pantoea was abundant in the north-east monsoon (51.8%). The dominant bacteria belonging to the known ice nucleating genera Pseudomonas, Pantoea, and Bacillus were chosen for the determination of their freezing temperatures using tube freeze assay technique. The onset freezing temperature of species belonging to Pseudomonas and Pantoea was recorded as −12 °C and for those species belonging to Bacillus it was found to be −14 °C. Further, the number of bacterial cells making up an ice nucleus was estimated at the temperatures ranging from −18 °C to −12 °C for all the ice nucleating bacteria and it was found to vary from 106 to 109 (cells/nucleus). © 2018 Elsevier Ltd

Atmospheric Environment

Characterization of bacterial diversity and ice-nucleating ability during different monsoon seasons over a southern tropical Indian region

Bioaerosols, which are ubiquitous in the earth's atmosphere, are poorly characterized in terms of their physical and chemical properties. Improved knowledge of their physical and chemical properties is essential to have a better understanding of their dispersion and long-range transport in the atmosphere and at the same time to assess their role as potential Ice Nuclei (IN). In the present work, possibly for the first time we report the morphological characteristics of bioaerosols from marine urban and high altitude continental regions in Southern India. The samples were collected using polycarbonate filter paper and analyzed using Scanning Electron Microscope (SEM) coupled with Energy-dispersive Spectra Detector (EDX/EDS). The observed bioaerosols exhibited great variability in their morphological features over this region of the world. At these contrasting environments, we found that fungal spores constituted the major fraction of the total observed bioaerosols. Pollen grains, plant and insect fragments, and lot of other non-identified bio-particles were also observed constituting the remaining fraction. Further, the classification of fungal spores exhibited strong variability over this region. For example, fungal spores of both Ascomycota and Basidiomycota class were seen in abundance in marine environment, while Ascomycota especially Cladosporium were seen in abundance in high altitude continental environment. Our findings also suggest that increase in diversity of bioaerosol particles at marine site appeared to coincide with precipitation. It appears that vast diversity in the morphological features of bioaerosols exists over this region, which should further be studied using advanced online techniques for better quantification under contrasting environments. However, the diversity observed in morphological characteristics of bioaerosols at these two contrasting locations is limited and restricted to these two sites and season of the year, and should therefore not be generalized over a large spatio-temporal scale; emphasizing the need for more similar studies covering larger geographical area. © 2015 Elsevier Ltd.

Morphological characteristics of bioaerosols from contrasting locations in southern tropical India - A case study

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 (&gt; 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 &lt; 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. © 2012 Author(s).

Atmospheric Chemistry and Physics

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

The fine particles serving as cloud condensation nuclei in pristine Amazonian rainforest air consist mostly of secondary organic aerosol. Their origin is enigmatic, however, because new particle formation in the atmosphere is not observed. Here, we show that the growth of organic aerosol particles can be initiated by potassium-salt - rich particles emitted by biota in the rainforest. These particles act as seeds for the condensation of low- or semi-volatile organic compounds from the atmospheric gas phase or multiphase oxidation of isoprene and terpenes. Our findings suggest that the primary emission of biogenic salt particles directly influences the number concentration of cloud condensation nuclei and affects the microphysics of cloud formation and precipitation over the rainforest.

Science

Biogenic potassium salt particles as seeds for secondary organic aerosol in the Amazon

Organic Geochemistry

Marine primary producer community during the mid-Cretaceous oceanic anoxic events (OAEs) 1a, 1b and 1d in the Vocontian Basin (SE France) evaluated from triaromatic steroids in sediments

All-optical automatic pollen identification: Towards an operational system

Bioaerosols in the Earth system: Climate, health, and ecosystem interactions

Journal	Data powered by TypesetAtmospheric Research
Publisher	Data powered by TypesetElsevier Ltd
ISSN	01698095
Open Access	Yes