Effects of Airflow and Changing Humidity on the Aerosolization of Respirable Fungal Fragments and Conidia of Botrytis cinerea

Abstract

<jats:title>ABSTRACT</jats:title><jats:p>The purpose of this study was to investigate the aerosolization of particles (micro- and macroconidia and fragments) from<jats:named-content content-type="genus-species">Botrytis cinerea</jats:named-content>cultures in relation to potential human inhalation in indoor environments. The influence of the following factors on the aerosolization of<jats:named-content content-type="genus-species">B. cinerea</jats:named-content>particles was studied: exposure to airflow, relative humidity (rh), changing rh, and plant or building materials. The aerodynamic diameter (<jats:italic>d</jats:italic><jats:sub><jats:italic>a</jats:italic></jats:sub>) and the respirable fraction of the aerosolized particles were determined. Conidia and fragments of<jats:named-content content-type="genus-species">B. cinerea</jats:named-content>were not aerosolized as a response to a decrease in the rh. In contrast, both micro- and macroconidia and fungal fragments were aerosolized when exposed to an airflow of 1.5 m s<jats:sup>−1</jats:sup>or 0.5 m s<jats:sup>−1</jats:sup>. Significantly more particles of microconidial size and fragment size were aerosolized at a low rh (18 to 40% rh) than at a higher rh (60 to 80% rh) when cultures were exposed to airflow. The size of the respirable fraction of the aerosolized particles was dependent on the rh but not on the growth material. At high rh, about 30% of the aerosolized particles were of respirable size, while at low rh, about 70% were of respirable size. During low rh, more fungal (1→3)-β-<jats:sc>d</jats:sc>-glucan and chitinase were aerosolized than during high rh. In conclusion, exposure to external physical forces such as airflow is necessary for the aerosolization of particles from<jats:named-content content-type="genus-species">B. cinerea</jats:named-content>. The amount and size distribution are highly affected by the rh, and more particles of respirable sizes were aerosolized at low rh than at high rh.</jats:p>

Passive Release of Fungal Spores from Synthetic Solid Waste Surfaces

“…Kildesø et al (2003) used a rotating air source to aerosolize and measure fungal spores grown on a gypsum board using an aerodynamic particle sizer (APS) and observed variation of fungal spore flux with fungus type. Madsen et al (2012) using a similar setup observed that spore release increased with decreasing air relative humidity. Gorny et al (2003) used a specially designed flow through chamber to measure fungal spores release from an agar surface and a ceiling tile using an optical particle counter.…”

Characterization of free amino acids, bacteria and fungi in size-segregated atmospheric aerosols in boreal forest: seasonal patterns, abundances and size distributions

“…In addition, the size of fungal spores has been found to depend on the relative humidity, i.e. higher the relative humidity is, the larger the spores are (Reponen et al, 1996;Madsen, 2012). The spores of basidiomycete fungi are in general larger than those of ascomycete (Reponen et al, 2001;Manninen et al, 2014;Hussein et al, 2013;, and the basidiomycete fungi are known to sporulate mainly during autumn when the relative humidity is high (Kauserud et al, 2011).…”

“…According to , the majority of the fungal DNA detected during summer and autumn is from fungal species belonging to Basidiomycota. Based on previous results , 2012, we have assumed that most the fungal DNA collected on our filters is also derived from basidiomycete fungi. Because only a few 18S rDNA regions of fungi are fully annotated, we have selected the P. radiata as a model basidiomycete fungus and calculated the gene copy numbers to fungal cells based on the assumption that all fungi in this experiment have approximately the same number of 18S rDNA gene copies as this fungus has (Kuuskeri et al, 2016).…”

Seasonal Variations of Indoor Microbial Exposures and Their Relation to Temperature, Relative Humidity, and Air Exchange Rate

“…Such parameters include the temperature and relative humidity (RH) of the air, both indoors and outdoors. In fact, the relative humidity has been shown to have profound effects on spore and particle release from fungal structures with which surfaces are infested (26,39). Denmark is located in northern Europe and experiences a temperate climate.…”