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.
- SourceAvailable from: Olli Sippula[Show abstract] [Hide abstract]
ABSTRACT: Background Ambient air particulate matter (PM) is increasingly considered to be a causal factor evoking severe adverse health effects. People spend the majority of their time indoors, which should be taken into account especially in future risk assessments, when the role of outdoor air particles transported into indoor air is considered. Therefore, there is an urgent need for characterization of possible sources seasonally for harmful health outcomes both indoors and outdoors.Methods In this study, we collected size-segregated (PM10¿2.5, PM2.5¿0.2) particulate samples with a high volume cascade impactor (HVCI) simultaneously both indoors and outdoors of a new single family detached house at four different seasons. The chemical composition of the samples was analyzed as was the presence of microbes. Mouse macrophages were exposed to PM samples for 24 hours. Thereafter, the levels of the proinflammatory cytokines, NO-production, cytotoxicity and changes in the cell cycle were investigated. The putative sources of the most toxic groups of constituents were resolved by using the principal component analysis (PCA) and pairwise dependencies of the variables were detected with Spearman correlation.ResultsSource-related toxicological responses clearly varied according to season. The role of outdoor sources in indoor air quality was significant only in the warm seasons and the significance of outdoor microbes was also larger in the indoor air. During wintertime, the role of indoor sources of the particles was more significant, as was also the case for microbes. With respect to the outdoor sources, soil-derived particles during a road dust episode and local wood combustion in wintertime were the most important factors inducing toxicological responses.Conclusions Even though there were clear seasonal differences in the abilities of indoor and outdoor air to induce inflammatory and cytotoxic responses, there were relatively small differences in the chemical composition of the particles responsible of those effects. Outdoor sources have only a limited effect on indoor air quality in a newly built house with a modern ventilation system at least in a low air pollution environment. The most important sources for adverse health related toxicological effects were related to soil-derived constituents, local combustion emissions and microbes.Particle and Fibre Toxicology 11/2014; 11(1):60. DOI:10.1186/s12989-014-0060-6 · 6.99 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: The respirable particles in both outdoor and indoor air contain several different components that are considered to have adverse health effects; e.g., polycyclic aromatic hydrocarbons (PAHs), various metals and microbial species. In this study, size segregated particle samples were collected for chemical, microbial and toxicological analyses from the indoor and outdoor air during each season of the year. The indoor sampling was carried out in a new, detached house with a novel sampling approach. The inorganic species accounted for 8–43% of the total respirable particles. The highest fine particle metal concentrations, both outdoors and indoors, were observed during summer, when the air quality was affected by wildfire smoke plumes, while in coarse particles the total metal concentrations were the highest during the spring, due to the high contribution from mineral dust. The PAH concentrations were 1.3 to 4.8 times higher in outdoor than in indoor air, and they were clearly the highest during winter, most probably due to residential heating, which is a major PAH source. PAHs with four rings had the largest contribution to the total PAHs. Microbial DNA was observed in all size classes, but the highest concentrations were measured in the coarse (PM 2.5–10) fraction. The microbial concentrations were higher in the indoor air samples during winter, while in the outdoor ones during summer.Aerosol and Air Quality Research 07/2013; 13:1212-1230. DOI:10.4209/aaqr.2012.11.0300 · 2.66 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: This study examined the relative adequacy of active landfills between states in Malaysia. The percentages of closed landfills were determined. The accessibility and loading of the landfills were examined. The characteristics of each landfill studied were noted. The study involved the compilation and analyses of data on groundwater, stream water and current land use surrounding landfills. Results of the study showed that the number of active landfills was not adequate to handle solid waste disposal. The potential of alternative approaches was examined and discussed.CLEAN - Soil Air Water 11/2013; 41(11). DOI:10.1002/clen.201200316 · 2.05 Impact Factor