Characterization of Chemical and Microbial Species from Size-Segregated Indoor and Outdoor Particulate Samples

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.

Role of microbial and chemical composition in toxicological properties of indoor and outdoor air particulate matter

“…This view is supported by the data showing clearly their highest concentrations in the PM 10–2.5 outdoor samples in the springtime during the road dust episode [28]. In the PCA, it was found that soil related constituents in the indoor samples increased disturbances in mitochondrial activity and cytotoxicity index, while no such association was found in the samples collected outdoors.…”

“…The detailed description of the chemical composition of the samples has been presented in Sippula et al [28] and their toxicological responses reported by Happo et al [29] and collected to Additional files 1 and 2. Briefly, despite the outdoor-to-indoor-transport of the particles, it was found that indoor sources dominated the toxicological responses of the particles found inside the house.…”

“…In this study set-up, the samples were collected in parallel from the indoor and outdoor air of a new single family house in four different seasons. The samples were characterized for their chemical and microbial properties [28] and their effects on inflammation, cytotoxicity as well as changes in the cell cycle were examined [29]. It was found that the PM 10 mass concentrations indoors and outdoors were nearly at the same level, but they differed in their chemical and microbial contents in terms of particle size-ranges, seasons as well as between indoor and outdoor air.…”

“…In an attempt to reveal chemical constituents and microbes that were responsible for the detected toxicological responses, we subjected this combined large multidisciplinary data set to a statistical analysis which included in-depth data from four seasonal sampling campaigns focusing on chemical and microbiological PM characteristics [28] and toxicological properties [29] of the very same PM samples. The aim of this study was to reveal possible connections between the chemical constituents and microbe concentrations and induced toxicological responses by using principal component analysis (PCA) and Spearman’s correlation test.…”

Total Suspended Particulate Matter (TSP ) and its Associated Heavy Metals in Atmosphere on the Western Coast of Saudi Arabia

“…Ambient levels and composition of PM depend on the emission sources and metrological conditions [2][3][4][5][6]. PM is a complex mixture of particles of different origins with large surface areas, and the significant portion of its mass is made up of inorganic constituents (trace metals and water-soluble ions), which plays an important role in aerosol chemistry [3].…”