Background: Particulate matter, microorganisms in air and environmental conditions present a potential risk to museum collections. There are also limited studies of simultaneous measurements of airborne particles and microorganisms inside museums and the effects of seasonal variations. Therefore, extensive indoor/outdoor measurements of particulate matter mass/number concentrations and viable, cultivable microbial load were performed in two museums and a library in Greece for a period of 2 years at selected time intervals. The culture heritage collections are located at coastal (Historical Museum of Crete in Heraklion), urban (Criminology Museum of the University of Athens) and mountainous (Neophytos Doukas Library in Zagori) environments and their collections consist mainly of organic materials. Measurements of inhalable particulate mass (PM 10 , PM 2.5 , PM 1) and viable, cultivable airborne microorganism concentrations (heterotrophic bacteria, cellulose metabolizing bacteria, acid producing bacteria and mesophilic fungi) in air were performed. Results and conclusions: The indoor PM 10 and microbial concentrations were higher than the outdoor levels showing the influence of the indoor sources, such as the presence of people and indoor activities, as well as, anthropogenic outdoor sources, and natural emissions. Elevated PM 1 particle number concentrations were also encountered in the Historical Museum of Crete in Heraklion and the Criminology Museum of the University of Athens due to the high anthropogenic emissions of the urban areas. The lowest concentrations of viable, cultivable airborne microorganisms were measured in the Historical Museum of Crete at the coastal site, which encounters also well controlled microclimatic conditions. In comparison to the other two naturally ventilated sites, the highest concentrations of viable, cultivable airborne fungi were measured in the Neophytos Doukas Library at the mountainous site, whereas the highest concentrations of viable, cultivable airborne heterotrophic bacteria were measured in the Criminology Museum of the University of Athens at an urban site, where mummified tissues and dry specimens are exhibited. The closed showcases of the two museums and the library could only protect the exhibits from viable, cultivable airborne fungi, but not from specific categories of bacteria. Acid producing bacteria in the Historical Museum of Crete, cellulose metabolizing bacteria in the Neophytos Doukas Library, and opportunistic pathogenic heterotrophic bacteria in the Criminology Museum of the University of Athens showed to be enriched inside the closed showcases.
Airborne particles, bacteria and fungi consist main determinants of indoor air quality. In this study, these characteristics were investigated in two exhibition halls of the Historical Museum of Crete, in comparison with the outdoor environment. In Zacharias Portalakis (ZP) hall, three air purifiers were operating during museum opening hours, as opposed to El Greco (EG) hall. A significant part of ultrafine (< 1 μm) particles was efficiently removed by the air purifiers in ZP hall. Airborne coarse particles PN2.5–10 were associated with human occupancy in both halls, indicating transportation from visitors and resuspension as possible sources. Average airborne bacterial concentration was also lower in ZP than in EG hall, assessed by both molecular and culture-dependent methods. The bacterial and fungal communities of both indoor halls were distinct from the outdoor counterpart. Micrococcus and Staphylococcus, in terms of bacteria, and Alternaria and Malassezia, in terms of fungi, were the most abundant genera indoors, most of them being human-related. Hierarchical clustering of indoor samples indicated that EG hall bacteria were similar to ZP hall bacteria collected on the same day, but varied between different sampling dates. This observation, together with the bacterial beta-diversity analysis, implied that both indoor halls probably shared common bacterial source(s), while the respective fungal pattern of the two indoor halls was found significantly separated. The outdoor air contribution in EG and ZP hall bacterial profile presented a comparable fluctuation pattern; this was not observed for fungi, probably indicating the complexity of potential sources for different fungal taxa.
Studying air quality in healthcare facilities comprises of identification of the contaminant sources, their dispersion, and impact on indoor air. 1,2 Considering as ultimate purpose pathogen mitigation, minimization of the acquired infections both for the patients and the personnel is a challenging issue, 3,4 not only because of the direct contact with the contaminant sources but also due to their great variability in their characteristics and properties.Airborne particulate contaminants consist mainly of aerosols and/or particles of biological matter, that is, bioaerosols. Airborne aerosol properties vary considerably depending on their size and chemical/biological composition. 5 In turn, their size and composition are governed by their origin (natural environment, anthropogenic
The relationship between the viable airborne bacterial and fungal concentrations and the respirable particulate matter with aerodynamic diameter less than 10 μm (PM10), 2.5 μm (PM2.5), and 1 μm (PM1) in the ambient air was studied. An Andersen six stage viable particle sampler and a MAS 100 sampler were used for microbial measurements. Duplicates of samples were collected at each sampling period (20 campaigns in total) at a residential site in the city of Chania (Crete, Greece) during April, May and June 2008. Mean concentration of the total sum of the six size fractions was 79 + 41 CFU m-3 for mesophilic heterotrophic bacteria, whereas for mesophilic fungi it was five times higher (395 + 338 CFU m-3). Particulate matter measurements at the same time period at the same site revealed that the mean concentrations of PM10, PM2.5, and PM1 were 46 + 14, 35 + 14, and 28 + 12 μg m-3, respectively, whereas the mean cumulate counts of PM1 particles was 5,059 + 1,973 particles cm-3. The mean arithmetic concentration of the size distribution of the airborne fungi had a maximum at aerodynamic diameters between 2.1 and 3.3 μm. However, a maximum was not observed for the mean arithmetic concentration of the size distribution of the airborne heterotrophic bacteria. It was also observed that concentrations of airborne bacteria and fungi outdoors were highly variable and do not correlate with the particle number (PM1) or mass concentration of PM10, PM2.5 and PM1. Thereby, the R2-values in all correlations were less than 0.3. However, the concentrations of airborne bacteria and fungi were decreased with increasing mass concentrations of PM10, PM2.5, or PM1 while were increased with increasing number concentration of PM1. In addition, the concentrations of airborne bacteria were increased with increasing concentrations of airborne fungi. Finally, the microbial or the particulate matter data did not correlate with meteorological parameters, such as temperature, relative humidity, wind speed and UV radiation in ambient conditions.
The daily deposited dose of bioaerosols and particle mass or number in the human respiratory tract using an exposure dose model (ExDoM2) was quantified in the present study. The dose was calculated for the extrathoracic (ET), tracheobronchial (TB), and alveolar-interstitial (AI) regions of the human respiratory tract. The calculations were performed for viable, cultivable airborne heterotrophic bacteria, mesophilic fast-growing fungi, and total coliforms at a municipal wastewater treatment plant (WWTP) located at a suburban area at a Mediterranean site. The human dose was determined using data from two locations at the WWTP which correspond to two different wastewater treatment stages (aerated grit chamber (indoor) and primary settling tanks (outdoor)) and one outdoor location at the urban background site. In addition, the model simulations were performed for two exposure periods (March to April and May to June 2008). Higher daily deposited dose in the total human respiratory tract was observed for heterotrophic bacteria at the aerated grit chamber, whereas lower values of heterotrophic bacteria were observed at the primary settling tanks. These findings were associated with the corresponding stage of wastewater treatment activities and may be valuable information for determining future dose–response relationships. In addition, higher daily deposited dose was determined in the ET region for the three categories of bioaerosols. Regarding PM10 and PN1, the higher daily deposited dose received by a worker at the aerated grit chamber. Finally, the hazard quotients were estimated and the results showed that the non-carcinogenic effects can be ignored for bioaerosols and PM10 except for workers present at aerated grit chamber. Regarding PM2.5, the non-carcinogenic effects are of concern and cannot be ignored for all cases.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.