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.

Primary biological aerosol particles in the atmosphere: a review

“…It has often been found that numbers are greatest in summer and autumn (Bovallius et al, 1978;Jones and Cookson, 1983;di Giorgio et al, 1996;Tong and Lighthart, 1999;Fang et al, 2007;Kaarkainen et al, 2008), although exceptions exist; Fahlgren et al (2010) found that bacteria counts at a coastal site were highest in winter, which they attributed to a strong winter marine sea spray source. Over a period of 1 d, bacteria have usually been observed to exhibit a peak airborne concentration in the morning and evening (Lighthart and Shaffer, 1995;Shaffer and Lighthart, 1997;Fang et al, 2007).…”

Air Microbial Contamination at the Holy Mosque, Makkah, Saudi Arabia

“…The number and composition of airborne microorganisms have increased in the urban and rural areas 1 .The presence of microorganisms depends on seasonality, geographical conditions, meteorological factors, type of sources 2, 3 4 , and air pollution 5 .Airborne microorganisms may contributẽ 20%, 22% and 10% of the total particulate matters in the remote continental, populated-continental, and remote maritime environments, respectively 6 . The concentrations and composition of airborne microorganisms undergoes daily, weekly and seasonally changes 7 .…”

Annual Variations in the Diversity, Viability, and Origin of Airborne Bacteria

“…In addition, sampling location characteristics (e.g., altitude and urban versus rural sites) and temporal aspects have a large influence on the number and identity of collected bacteria. Nevertheless, some general trends can be outlined based on published sources: bacterial CFU counts are often higher in urban than in rural sites when samples are taken in the same geographic region (11,18), bacterial CFU counts seem generally lower in coastal than inland areas (11,43), and both fungi and bacteria occur in higher numbers in the air in summer and autumn in both rural and urban environments (11,18,20,27). Bacterial abundance also varies diurnally: in urban and rural locations, the highest CFU counts have been found in the morning and evening (20,29,43).…”