Bioaerosol

About: Bioaerosol is a(n) research topic. Over the lifetime, 1347 publication(s) have been published within this topic receiving 34791 citation(s).

The effects of meteorological factors on atmospheric bioaerosol concentrations--a review.

Abstract: Over land surfaces a quarter of the total airborne particulate may be made up of biological material in the form of pollen, fungal spores, bacteria, viruses, or fragments of plant and animal matter. Meteorological variables affect the initial release of this material and its dispersal once airborne. Temperature and water availability will affect the size of the source and will control the release of some actively released fungal spores. Inertly released material will become airborne when the drying of the surface reduces bonding forces, and when the material is disrupted by sufficiently strong air movement or by mechanical disturbance. The wind speed necessary to disrupt material is noted to be less on a plant surface than on the ground surface. Measurements of the concentrations of airborne material near dominant sources are reviewed for both area sources, and for point sources such as sewage and waste treatment works, agricultural practices, and diseased animals. The concentration of airborne material remote from sources is considered along with the effects of on and off shore winds and some examples of long distance transport of material. The vertical concentration of bacteria is noted to decline less rapidly than that of fungal spores. The short-term variation of pollen, fungal spore, and bacterial concentrations are also considered.

Inhaling to mitigate exhaled bioaerosols

Abstract: Humans commonly exhale aerosols comprised of small droplets of airway-lining fluid during normal breathing. These “exhaled bioaerosols” may carry airborne pathogens and thereby magnify the spread of certain infectious diseases, such as influenza, tuberculosis, and severe acute respiratory syndrome. We hypothesize that, by altering lung airway surface properties through an inhaled nontoxic aerosol, we might substantially diminish the number of exhaled bioaerosol droplets and thereby provide a simple means to potentially mitigate the spread of airborne infectious disease independently of the identity of the airborne pathogen or the nature of any specific therapy. We find that some normal human subjects expire many more bioaerosol particles than other individuals during quiet breathing and therefore bear the burden of production of exhaled bioaerosols. Administering nebulized isotonic saline to these “high-producer” individuals diminishes the number of exhaled bioaerosol particles expired by 72.10 ± 8.19% for up to 6 h. In vitro and in vivo experiments with saline and surfactants suggest that the mechanism of action of the nebulized saline relates to modification of the physical properties of the airway-lining fluid, notably surface tension.

Bacterial and fungal aerosol in indoor environment in Upper Silesia, Poland

Abstract: The purpose of this study was to find the typical concentration levels of bacterial and fungal bioaerosol in healthy and moldy homes as well as in office rooms in Upper Silesia Industrial Zone. Airborne bacteria and fungi were collected using the 6-stage Andersen impactor inside and outside of buildings. It was found that the typical level of bacterial aerosol indoors is about 103 CFU m−3 in homes and 102 CFU m−3 in offices. Only Micrococcus spp was present in all homes studied, constituting 36% of the bacterial genera. The second most common was Staphylococcus epidermidis, present in 76% of homes and constituting 14% of the total. The concentration of fungal aerosol in winter ranged from 10 to 102 CFU m−3 in healthy homes and from 10 to 103 CFU m−3 in homes with mold problems. In summer these values were elevated reaching 103 CFU m−3 in healthy homes and 103–104 CFU m−3 in moldy buildings. In healthy homes the relative concentration of observed species, including Penicillium, ranged from 3 to about 50% while in moldy homes the highest concentration of Penicillium accounted for 90% of the total fungi. However, the differences between viable fungal species as well as concentrations observed in moldy and healthy homes seem to be too small to be a reason of significantly higher risk for allergic asthma symptoms in any group of buildings. Comparison of the respirable fraction of airborne bacteria and fungi with literature data suggests that the percentage of respirable fungi and bacteria is generally not dependent on the type of home, building material, geographical factors and particulate air pollution.

Seasonal variability in bacterial and fungal diversity of the near-surface atmosphere.

Abstract: Bacteria and fungi are ubiquitous throughout the Earth's lower atmosphere where they often represent an important component of atmospheric aerosols with the potential to impact human health and atmospheric dynamics. However, the diversity, composition, and spatiotemporal dynamics of these airborne microbes remain poorly understood. We performed a comprehensive analysis of airborne microbes across two aerosol size fractions at urban and rural sites in the Colorado Front Range over a 14-month period. Coarse (PM10-2.5) and fine (PM2.5) particulate matter samples were collected at weekly intervals with both bacterial and fungal diversity assessed via high-throughput sequencing. The diversity and composition of the airborne communities varied across the sites, between the two size fractions, and over time. Bacteria were the dominant type of bioaerosol in the collected air samples, while fungi and plants (pollen) made up the remainder, with the relative abundances of fungi peaking during the spring and summer months. As bacteria made up the majority of bioaerosol particles, we analyzed the bacterial communities in greater detail using a bacterial-specific 16S rRNA gene sequencing approach. Overall, bacterial taxonomic richness and the relative abundances of specific bacterial taxa exhibited significant patterns of seasonality. Likewise, airborne bacterial communities varied significantly between sites and across aerosol size fractions. Source-tracking analyses indicate that soils and leaves represented important sources of bacteria to the near-surface atmosphere across all locations with cow fecal bacteria also representing an important source of bioaerosols at the more rural sites during early fall and early spring. Together, these data suggest that a complex set of environmental factors, including changes in atmospheric conditions and shifts in the relative importance of available microbial sources, act to control the composition of microbial bioaerosols in rural and urban environments.

Arabitol and mannitol as tracers for the quantification of airborne fungal spores

Abstract: Fungal spores constitute a sizeable fraction of coarse organic carbon (OC) in the atmospheric aerosol. In order to avoid tedious spore count methods, tracers for quantifying the spore-OC in atmospheric aerosol are sought. Arabitol and mannitol have been proposed as such tracers, since no other emission sources for these compounds have been reported. By parallel investigations of spore counts and tracer determinations from PM 10 filter samples we could derive quantitative relationships between the amounts of tracer compounds and the numbers of spores in the atmosphere for different sites in the area of Vienna. We obtained over all average relationships of 1.2 pg arabitol spore −1 , with a range of 0.8–1.8, and 1.7 pg mannitol spore −1 , with a range of 1.2–2.4, with a clear site dependence. Thus, using these conversion factors from spore counts to spore-OC and spore-mass, along with analytical data for arabitol or mannitol in filter samples, the contribution of fungal spores to the OC and to the mass balance of atmospheric aerosol particles can be estimated.