Seasonal Variation in Airborne Microbial Concentrations and Diversity at Landfill, Urban and Rural Sites
ABSTRACT Microbes are present everywhere in outdoor air. However, the general characterization of outdoor air mycobiota and bacterial flora is incomplete. In this study, seasonal variations in outdoor air microbial concentrations and differences between a landfill, urban and rural sites were compared. Samples were collected monthly for a period of one year. Airborne dust samples were collected onto polyvinyl chloride filters. Filter samples were analyzed for ergosterol, and 14 species or assay groups of fungi and for the bacterial genus Streptomyces by using quantitative PCR. Viable bacteria and fungi were collected with a cascade impactor twice each month from the three sampling sites. The concentrations in the different sampling sites varied depending on the species. The concentrations of Penicillium and Aspergillus species were significantly higher in the waste center compared with the other sites, while the concentration of Cladosporium spp. was highest in the rural area. The highest concentrations of Streptomyces and Cladosporium species were observed in warmer weather periods. Similar observations were made for ergosterol. Group and species seasonal variation was less distinct for Penicillium and Aspergillus. According to the present results, both season and environment are determinants of microbial communities in outdoor air.
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ABSTRACT: The atmosphere is host to an omnipresent bacterial community that may influence fundamental atmospheric processes such as cloud formation and precipitation onset. Knowledge of this bacterial com-munity is scarce, particularly in air masses relevant to cloud formation. Using a light aircraft, we sampled above the atmospheric boundary layer—that is, at heights at which cloud condensation occurs—over coastal areas of Sweden and Denmark in summer 2009. Enumeration indicated total bacterial numbers of 4 9 10 1 to 1.8 9 10 3 m -3 air and colony-forming units of 0–6 bacteria m -3 air. 16S rRNA gene libraries constructed from samples collected above the Baltic Sea coast revealed a highly diverse bacterial commu-nity dominated by species belonging to the genera Sphingomonas and Pseudomonas. Bacterial species known to carry ice-nucleating proteins were found in several samples. Modeled back trajectories suggested the potential sources of the sampled bacteria to be diverse geographic regions, including both marine and terrestrial environments in the northern hemisphere. Several samples contained 16S rRNA genes from plant chloroplasts, confirming a terrestrial contribu-tion to these samples. Interestingly, the airborne bacterial community displayed an apparent seasonal succession that we tentatively ascribe to in situ succession in the atmosphere.Aerobiologia 12/2012; 28(4):481-498. · 1.33 Impact Factor
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ABSTRACT: Microbial particles can readily be released into the air from different types of man-made sources such as waste operations. Microbiological emissions from different biological sources and their dispersion may be an issue of concern for area planning and for nearby residents. This study was designed to determine the concentrations and diversity of microbiological emissions from four different man-made source environments: waste center with composting windrows, sewage treatment plant, farming environment, and cattle manure spreading. Samples of airborne particles were collected onto polyvinyl chloride filters at three distances along the prevailing downwind direction, from each source environment during a period of approximately 1 week. These samples were analyzed for 13 species or assay groups of fungi, bacterial genus Streptomyces, and Gram-positive and -negative bacteria using quantitative polymerase chain reaction (PCR). Samples for determining the concentrations of viable fungi and bacteria were collected from all environments using a six-stage impactor. The results show that there were variations in the microbial diversity between the source environments. Specifically, composting was a major source for the fungal genera Aspergillus and Penicillium, particularly for Aspergillus fumigatus, and for the bacterial genus Streptomyces. Although the microbial concentrations in the sewage treatment plant area were significantly higher than those at 50 or 200 m distance from the plant area, in the farming environment or cattle manure spreading area, no significant difference was observed between different distances from the source. In summary, elevated concentrations of microbes that differ from background can only be detected within a few hundred meters from the source. This finding, reported earlier for culturable bacteria and fungi, could thus be confirmed using molecular methods that cover both culturable and nonculturable microbial material.Journal of the Air & Waste Management Association (1995) 12/2011; 61(12):1382-92. · 1.20 Impact Factor
- American journal of men's health 01/2011; 8(3):227-227. · 1.15 Impact Factor