TY - JOUR TI - Investigation of bioaerosol characterization bias due to aerosolization and sampling DO - https://doi.org/doi:10.7282/T3S75J6V PY - 2015 AB - Bioaerosols have been investigated for their adverse effects on human health and also their roles in cloud formation, precipitation and atmospheric chemical reactions. In these studies, it is often necessary to collect biological cells from the airborne state or to disperse the cells into the air using a variety of sampling and aerosolization devices. These devices inevitably exert stress on the cells and result in changes in their biological characteristics, e.g. loss of culturability, impairment of cell membrane, and change in cellular activities. It is highly likely that after experiencing such stress, collected microorganisms are not representative of cells prior to sampling and aerosolization, and thus could introduce biases in their characterization. In this dissertation, the potential bioaerosol characterization biases induced by several commonly used sampling and aerosolization devices were investigated. The stress experienced by E. coli during aerosolization was found to depend on a particular aerosolization device. Particularly, a newly developed pneumatic nebulizer, the Single-Pass Aerosolizer, was shown to better preserve cell culturability and membrane integrity compared to the commonly used Collison nebulizer at similar biological particles output concentrations. Several bioaerosol samplers that employ filtration, impingement, impaction and electrostatic precipitation for sample collection were tested with respect to their effects on the cell membrane integrity and cellular 16S rRNA content of Escherichia coli cells. Sampling stress resulted in severe membrane impairment to E. coli aerosols, leading to the release of genomic DNA as extracellular molecules. Extracellular DNA should be taken into account when analyzing bioaerosol samples to more accurately quantify bacterial presence. Cell membrane damage to bioaerosols depended on which sampler was used and could be reduced by modifying specific operational parameters. E. coli cells exhibited variation in 16S ribosomal RNA (rRNA) level when exposed to long-term air sampling in laboratory experiment, suggesting a change of biological activity in response to sampling stress. The importance of this effect for those taxa in airborne bacterial community from a variety of environments should be examined. The abundance of bacterial 16S rRNA in bioaerosols collected from an outdoor environment was about two orders of magnitude higher than that of 16S rRNA gene. However, the sampler-dependent bias effect on analysis of 16S rRNA sequences for bacterial community composition was minimal in investigated outdoor bioaerosols. KW - Environmental Sciences KW - Biosensors KW - Aerosols--Measurement LA - eng ER -