Abstract
<strong class="journal-contentHeaderColor">Abstract.</strong> The interplay of bio-aerosol dispersion and impact, meteorology, and air quality is gaining increasing interest in the wide spectrum of atmospheric sciences. Experiments conducted inside confined artificial environments, such as atmospheric simulation chambers (ASCs), where atmospheric conditions and composition are controlled, can provide valuable information on bio-aerosol viability, dispersion, and impact. We focus here on the reproducible aerosolization and injection of viable microorganisms into an ASC, the first and crucial step of any experimental protocol to expose bio-aerosols to different atmospheric conditions. We compare the performance of three nebulizers specifically designed for bio-aerosol applications: the Collison nebulizer, the Blaustein Atomizing Modules (BLAM), and the Sparging Liquid Aerosol Generator (SLAG), all manufactured and commercialized by CH TECHNOLOGIES. The comparison refers to operating conditions and the concentration of viable bacteria at the nebulizer outlet, with the final goal being to measure the reproducibility of the nebulization procedures and assess their application in experiments inside ASCs. A typical bacterial test model, <i>Escherichia coli</i> (ATCC<sup>®</sup> 25922â¢), was selected for such characterization. Bacteria suspensions with a concentration around 10<span class="inline-formula"><sup>8</sup></span>âCFUâmL<span class="inline-formula"><sup>â1</sup></span> were first aerosolized at different air pressures and collected by a liquid impinger to obtain a correlation curve between airflow and nebulized bacteria for each generator. Afterwards, bacteria were aerosolized inside the atmospheric simulation chamber ChAMBRe (Chamber for Aerosol Modelling and Bio-aerosol Research) to measure the reproducibility of the whole procedure. An overall reproducibility of 11â% (i.e., standard deviation of the results obtained with the three nebulizers) was obtained with each nebulizer through a set of baseline experiments.
Highlights
The term primary biological aerosol particles (PBAPs) refers to particles of biological origin suspended in gaseous medium, including microorganisms and fragments of biological materials
The aerosolization air flow varied in the range of 1.4–3.5 L min−1 for the Blaustein Atomizing Modules (BLAM) and 2–5 L min−1 for the Sparging Liquid Aerosol Generator (SLAG) and Collison nebulizers
The bacteria suspension was supplied to the BLAM and SLAG devices at the same liquid flow rate of 0.4 mL min−1
Summary
The term primary biological aerosol particles (PBAPs) refers to particles of biological origin suspended in gaseous medium, including microorganisms and fragments of biological materials. Biological aerosol particles such as pollen, fungal spores, and bacteria can cause many adverse health effects and influence Earth’s climate (Després et al, 2012). Bacteria are ubiquitous in the atmosphere, with concentrations of bacterial cells typically greater than 1 × 104 m−3 over land and, due to their small size, bacteria have a long atmospheric residence time (several days or more) and can be transported over long distances of up to thousands of kilometers (Burrows et al, 2009; Federici et al, 2018). The referenced experiments were performed using atmospheric simulation chambers (ASCs), which are small to large-scale facilities
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