Quantitative profiling of built environment bacterial and fungal communities reveals dynamic material dependent growth patterns and microbial interactions

Indoor microbial communities vary in composition and diversity depending on material type, moisture levels, and occupancy. In this study, we integrated bacterial cell counting, fungal biomass estimation, and fluorescence-assisted cell sorting (FACS) with amplicon sequencing of bacterial (16S rRNA) and fungal (ITS) communities to investigate the influence of wetting on medium density fiberboard (MDF) and gypsum wallboard. Surface samples were collected longitudinally from wetted materials maintained at high relative humidity (~95%). Bacterial and fungal growth patterns were strongly time-dependent and material-specific. Fungal growth phenotypes differed between materials: spores dominated MDF surfaces while fungi transitioned from spores to hyphae on gypsum. FACS confirmed that most of the bacterial cells were intact (viable) on both materials over the course of the study. Integrated cell count and biomass data (quantitative profiling) revealed that small changes in relative abundance often resulted from large changes in absolute abundance, while negative correlations in relative abundances were explained by rapid growth of only one group of bacteria or fungi. Comparisons of bacterial-bacterial and fungal-bacterial networks suggested a top-down control of fungi on bacterial growth, possibly via antibiotic production. In conclusion, quantitative profiling provides novel insights into microbial growth dynamics on building materials with potential implications for human health.     

Associations between respiratory infections and bacterial microbiome in student dormitories in Northern China

Recent studies reveal that the microbial diversity and composition in the respiratory tract are related to the susceptibility, development, and progression of respiratory infections. Indoor microorganisms can transmit into the respiratory tract through breathing, but their role in infections is unclear. Here, we present the first association study between the indoor microbiome and respiratory infections. In total, 357 students living in 86 dormitory rooms in Shanxi University were randomly selected to survey symptoms of infections. Settled air dust was collected to characterize bacterial compositions by 16S rRNA sequencing. The overall microbial richness was not associated with respiratory infections, but microorganisms from specific phylogenetic classes showed various associations. Taxa richness and abundance of Actinobacteria were protectively associated with infections (P < .05). The abundance of several genera in Gammaproteobacteria, including Haemophilus, Klebsiella, Buttiauxella, and Raoultella, was positively associated with infections (P < .005). The role of these microorganisms was consistent with previous human microbiota studies. Building age was associated with the overall microbial composition variation in dormitories and negatively associated with three potential risk genera in Proteobacteria (P < .05). The weight of vacuum dust was positively associated with a protective genus, Micrococcus in Actinobacteria (P < .05).     

空气传播的生化袭击与建筑环境安全(1):综述

介绍了当今世界生化恐怖活动的现状与发展趋势,指出空气传播的生化袭击已对建筑物的安全构成了严重威胁。概述了生化袭击给建筑环境安全带来的新问题和国外的研究现状,具体分析了生化灾害的特点和我国建筑环境安全可能存在的问题,并进一步从生化袭击的防范、处置和事后恢复这三个方面讨论了建筑环境安全问题。     

Microbial exposures in moisture-damaged schools and associations with respiratory symptoms in students: A multi-country environmental exposure study

Moisture-damaged buildings are associated with respiratory symptoms and underlying diseases among building occupants, but the causative agent(s) remain a mystery. We first identified specific fungal and bacterial taxa in classrooms with moisture damage in Finnish and Dutch primary schools. We then investigated associations of the identified moisture damage indicators with respiratory symptoms in more than 2700 students. Finally, we explored whether exposure to specific taxa within the indoor microbiota may explain the association between moisture damage and respiratory health. Schools were assessed for moisture damage through detailed inspections, and the microbial composition of settled dust in electrostatic dustfall collectors was determined using marker-gene analysis. In Finland, there were several positive associations between particular microbial indicators (diversity, richness, individual taxa) and a respiratory symptom score, while in the Netherlands, the associations tended to be mostly inverse and statistically non-significant. In Finland, abundance of the Sphingomonas bacterial genus and endotoxin levels partially explained the associations between moisture damage and symptom score. A few microbial taxa explained part of the associations with health, but overall, the observed associations between damage-associated individual taxa and respiratory health were limited.     

Fluorescent biological aerosol particles: Concentrations,emissions, and exposures in a northern California residence

Residences represent an important site for bioaerosol exposure. We studied bioaerosol concentrations, emissions, and exposures in a single‐family residence in northern California with 2 occupants using real‐time instrumentation during 2 monitoring campaigns (8 weeks during August‐October 2016 and 5 weeks during January‐March 2017). Time‐ and size‐resolved fluorescent biological aerosol particles (FBAP) and total airborne particles were measured in real time in the kitchen using an ultraviolet aerodynamic particle sizer (UVAPS). Time‐resolved occupancy status, household activity data, air‐change rates, and spatial distribution of size‐resolved particles were also determined throughout the house. Occupant activities strongly influenced indoor FBAP levels. Indoor FBAP concentrations were an order of magnitude higher when the house was occupied than when the house was vacant. Applying an integral material‐balance approach, geometric mean of total FBAP emissions from human activities observed to perturb indoor levels were in the range of 10‐50 million particles per event. During the summer and winter campaigns, occupants spent an average of 10 and 8.5 hours per day, respectively, awake and at home. During these hours, the geometric mean daily‐averaged FBAP exposure concentration (1‐10 μm diameter) was similar for each subject at 40 particles/L for summer and 29 particles/L for winter.     

Size-resolved dynamics of indoor and outdoor fluorescent biological aerosol particles in a bedroom: A one-month case study in Singapore

This study evaluated the interrelations between indoor and outdoor bioaerosols in a bedroom under a living condition. Two wideband integrated bioaerosol sensors were utilized to measure indoor and outdoor particulate matter (PM) and fluorescent biological airborne particles (FBAPs), which were within a size range of 0.5-20 μm. Throughout this one-month case study, the median proportion of FBAPs in PM by number was 19% (5%; the interquartile range, hereafter) and 17% (3%) for indoors and outdoors, respectively, and those by mass were 78% (12%) and 55% (9%). According to the size-resolved data, FBAPs dominated above 2 and 3.5 μm indoors and outdoors, respectively. Comparing indoor upon outdoor ratios among occupancy and window conditions, the indoor FBAPs larger than 3.16 μm were dominated by indoor sources, while non-FBAPs were mainly from outdoors. The occupant dominated the indoor source of both FBAPs and non-FBAPs. Under awake and asleep, count- and mass-based mean emission rates were 45.9 and 18.7 × 10⁶ #/h and 5.02 and 2.83 mg/h, respectively. Based on indoor activities and local outdoor air quality in Singapore, this study recommended opening the window when awake and closing it during sleep to lower indoor bioaerosol exposure.     

Composition of bacterial and archaeal communities in freshwater sediments with different contamination levels (Lake Geneva, Switzerland)

The aim of this study was to compare the composition of bacterial and archaeal communities in contaminated sediments (Vidy Bay) with uncontaminated sediments (Ouchy area) of Lake Geneva using 16S rRNA clone libraries. Sediments of both sites were analysed for physicochemical characteristics including porewater composition, organic carbon, and heavy metals. Results show high concentrations of contaminants in sediments from Vidy. Particularly, high contents of fresh organic matter and nutrients led to intense mineralisation, which was dominated by sulphate-reduction and methanogenesis. The bacterial diversity in Vidy sediments was significantly different from the communities in the uncontaminated sediments. Phylogenetic analysis revealed a large proportion of Betaproteobacteria clones in Vidy sediments related to Dechloromonas sp., a group of dechlorinating and contaminant degrading bacteria. Deltaproteobacteria, including clones related to sulphate-reducing bacteria and Fe(III)-reducing bacteria (Geobacter sp.) were also more abundant in the contaminated sediments. The archaeal communities consisted essentially of methanogenic Euryarchaeota, mainly found in the contaminated sediments rich in organic matter. Multiple factor analysis revealed that the microbial community composition and the environmental variables were correlated at the two sites, which suggests that in addition to environmental parameters, pollution may be one of the factors affecting microbial community structure.     

Sick building syndrome—A case study in a multistory centrally air-conditioned building in the Delhi City

Recently, airtight envelope system has become popular in the design of office buildings to reduce heating and cooling loads. Maintaining allowable indoor air quality (IAQ) for such airtight buildings totally depends on mechanical ventilation systems. Subsequently, poor operation of the ventilation system in such office buildings causes ineffective removal of polluted indoor air, and displays a sign of “sick building syndrome” (SBS). User's perception is an important parameter for evaluating IAQ. A questionnaire study was carried out to investigate the prevalence of the SBS at a multistory centrally air-conditioned Airport Authority of India (AAI) building in the New Delhi city. Quantification of the perceptions of the users regarding IAQ was done by converting their responses to a SBS score. The quantified answers were then subjected to statistical analysis. Qualitative analysis of the questionnaire was carried out to evaluate relationships between SBS score and carbon dioxide (CO₂) and other parameters related to building and work environment. Quantitative analysis of IAQ was also conducted by monitoring indoor concentrations of four pollutants, namely, nitrogen dioxide (NO₂), sulphur dioxide (SO₂), suspended particulate matter (SPM) and carbon monoxide (CO). Concentrations of pollutants were complying with IAQ standards as given by ASHRAE and WHO. The SBS was higher on the third floor as compared to other floors and the control tower. The main symptoms prevailing were headache (51%), lethargy (50%), and dryness in body mucous (33%). The third floor and the control tower were affected by infiltration, mainly from entrance doors. A direct relation between the average SBS score and CO₂ concentration was found, i.e., the average SBS score increased with CO₂ concentration and vice versa, clearly signifying the usefulness of SBS score in IAQ.     

Functional bacterial and archaeal community structures of major trophic groups in a full-scale anaerobic sludge digester

Functional Bacteria and Archaea community structures of a full-scale anaerobic sludge digester were investigated by using a full-cycle 16S rRNA approach followed by microautoradiography (MAR)-fluorescent in situ hybridization (FISH) technique and micromanipulation. FISH analysis with a comprehensive set of 16S and 23S rRNA-targeted oligonucleotide probes based on 16S rRNA clone libraries revealed that the Gram-positive bacteria represented by probe HGC69A-hybridized Actinobacteria (8.5+/-1.4% of total 4', 6-diamidino-2-phenylindole (DAPI)-stained cells) and probe LGC354-hybridized Firmicutes (3.8+/-0.8%) were the major phylogenetic bacterial phyla, followed by Bacteroidetes (4.0+/-1.2%) and Chloroflexi (3.7+/-0.8%). The probe MX825-hybridized Methanosaeta (7.6+/-0.8%) was the most abundant archaeal group, followed by Methanomicrobiales (2.8+/-0.6%) and Methanobacteriaceae (2.7+/-0.4%). The functional community structures (diversity and relative abundance) of major trophic groups were quantitatively analyzed by MAR-FISH. The results revealed that glucose-degrading microbial community had higher abundance (ca. 10.6+/-4.9% of total DAPI-stained cells) and diversity (at least seven phylogenetic groups) as compared with fatty acid-utilizing microbial communities, which were more specialized to a few phylogenetic groups. Despite the dominance of Betaproteobacteria, members of Chloroflexi, Smithella, Syntrophomonas and Methanosaeta groups dominated the [(14)C]glucose-, [(14)C]propionate-, [(14)C]butyrate- and [(14)C]acetate-utilizing microorganism community, and accounted for 27.7+/-4.3%, 29.6+/-7.0%, 34.5+/-7.6% and 18.2+/-9.5%, respectively. In spite of low abundance (ca. 1%), the hitherto unknown metabolic functions of Spirochaeta and candidate phylum of TM7 as well as Synergistes were found to be glucose and acetate utilization, respectively.     

Assessment of phylogenetic diversity of bacterial microflora in drinking water using serial analysis of ribosomal sequence tags

We examined chlorinated drinking water samples from three different surface water treatment plants for bacterial 16S rDNA diversity using the serial analysis of V6 ribosomal sequence tag (SARST-V6) method. A considerable degree of diversity was observed in each sample, with an estimated richness ranging from 173 to 333 phylotypes. The community structure shows that there are differences in bacterial evenness between sampled sites. The taxonomic composition of the microbial communities was found to be dominated by members of the Proteobacteria (57.2-77.4%), broadly distributed among the classes Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Deltaproteobacteria. Additionally, a large proportion of sequences (6.3-36.5%) were found to be distantly related to database sequences of unknown phylogenetic affiliation. Given the apparent significance of this bacterial group in drinking water, a 16S rDNA analysis was performed and confirmed their presence and phylogeny. Notwithstanding the potential under-representation of certain bacterial phyla using the SARST-V6 primer pairs, as revealed by a refined computer algorithm, our results suggest that 16S rDNA corresponding to a variety of eubacterial groups can be detected in finished drinking water, suggesting that this water may contain a higher level of bacterial diversity than previously observed.     

Diversity in real estate developer behaviour: A case for research

The diversity of developer behaviour and its implications for the built environment require investigation. The paper illustrates this with six types of developer behaviour identified in two small but rapidly growing east coast Australian local government areas and comments on the their implications for the nature of urban development.     

Stability of the bacterial community in a pulp mill effluent treatment system during normal operation and a system shutdown

Currently, very little is known about the normal dynamics of microbial populations in wastewater treatment systems and the relationship between population dynamics and functional stability of treatment systems. We monitored the bacterial community in an oxygen activated sludge system at a pulp and paper mill during a 55-day period that included normal operation as well as an 11-day shutdown of the system and the subsequent start-up. Ribosomal intergenic spacer (RIS) length polymorphism fingerprints were very similar (57–88% similar) throughout the study period. Analysis of clone libraries of RIS-rRNA gene amplicons indicated that Proteobacteria affiliated with the genera Paracraurococcus and Acidovorax as well as a Green Nonsulfur Bacterium affiliated with the genus Roseiflexus were consistently among predominant members of the community. By comparison, wastewater treatment systems from different pulp mills yielded dissimilar fingerprints (9–17% similar), and their clone libraries had distinct predominant phylotypes. Our analysis strongly suggests that the composition of the bacterial community in the former treatment system was stable during normal operation as well as the shutdown and start-up. This stability coincided with functional stability, including consistent and nearly complete removal of biological oxygen demand.     

Diversity in real estate developer behaviour: A case for research

Abstract

The diversity of developer behaviour and its implications for the built environment require investigation. The paper illustrates this with six types of developer behaviour identified in two small but rapidly growing east coast Australian local government areas and comments on the their implications for the nature of urban development.     

建筑环境与能源应用工程 专业现代高素质人才培养探讨 ——以南京工业大学为例

回顾建筑环境与能源应用工程专业人才培养的历程,分析现代建筑业发展对建筑环境与能源应用工程专业高素质人才培养的需求,探讨面向未来建筑环境与能源应用工程专业高素质人才应具备的能力,提出建筑环境与能源应用工程专业高素质人才培养的有效举措。分析建筑环境与能源应用工程专业加强专业宣传的重要性,并提出强化专业宣传的方法与途径。论述专业教学理念应由知识传授转变为学生能力培养。阐明将大数据等创新技术纳入人才培养体系的必要性,提出利用互联网教学软件解决各课程之间知识点交叉衔接的问题。阐述构建完善的专业实训教学及创新创业训练体系在人才培养中的作用,提出以毕业设计为抓手,分层次多方案培养学生解决复杂工程问题的能力。     

Stimulation of microbial sulphate reduction in a constructed wetland: microbiological and geochemical analysis

Microbial sulphate reduction was stimulated successfully in enclosures installed in a constructed wetland. When sucrose (2.4mM) and NH(4)Cl (600 microM) were added to water in the test enclosures, the indigenous microbial community was able to remove over 90% of the sulphate, present as a contaminant from nearby mining activity at a concentration of 384 mg x l(-1) (4mM), over 50 days. Over 90% of the sucrose was also removed. Sulphate was not reduced in control enclosures containing no added sucrose or NH(4)Cl. Fermentation of sucrose by obligate anaerobes including Clostridium sp. and Bacteriodes sp. preceded sulphate reduction in the test enclosures. Sulphate reduction was biphasic, with maximum rates noted between 2-5 and 23-27 days after the addition of the growth substrates. Relatively unbiased 16S rDNA analysis suggested that nitrogen-fixing bacteria were important constituents of the microbial community in the test enclosures at day 23, suggesting that soluble nitrogen was limiting in the amended test enclosures during the experiment.     

Natural organic matter (NOM) removal and structural changes in the bacterial community during artificial groundwater recharge with humic lake water

This study evaluated the removal of natural organic matter (NOM) and structural changes in the microbial community during infiltration of humic lake water at three artificial groundwater recharge (AGR) sites in Finland. The three sites were at waterworks in H?meenlinna, Jyv?skyl? and Tuusula, sites A, B and C, respectively. Site A used groundwater recharge by both basin and sprinkling infiltration, site B used only sprinkling infiltration, and site C used only basin infiltration. Reductions of total organic carbon at sites A, B and C were 91%, 84% and 74%, respectively, in the winter, and 88%, 77% and 73%, respectively, in the summer. The Finnish national recommended value of 2 mg/l for TOC was achieved at all sites and the TOC of natural groundwater at site C was much lower, at 0.6 mg/l. Large molecular fractions of NOM were removed more efficiently than the smaller ones. Total amount of DAPI-stained cells decreased during infiltration at sites A, B and C in winter by 94%, 94% and 75% and in summer by 96%, 97% and 94%, respectively. Bacterial communities in raw waters and extracted groundwaters were diverse with changes occurring during infiltration, which was shown by DNA extraction followed by PCR of 16S rRNA genes and denaturing gradient gel electrophoresis (DGGE) fingerprinting. While the natural groundwater microbial community was diverse, it was different from that of the extracted groundwater in the AGR area. Simultaneous organic carbon removal and the decrease of bacterial counts during infiltration indicated biodegradation. In addition, the changing DGGE profiles during the process of infiltration, demonstrated that changing environmental conditions were reflected by changes in bacterial community composition.     

Flame retardants in building insulation: a case for re-evaluating building codes

US building codes balance the consideration of hazards to public safety, health and general welfare. Current codes require foam plastic insulation materials to have both protection by a thermal barrier and compliance with Steiner Tunnel test requirements. The Steiner Tunnel test is met by adding flame-retardant chemicals to the foam. Studies demonstrate that the Steiner Tunnel test does not give reliable fire safety results for foam plastic insulations. Foams that meet the Steiner Tunnel test still pose a fire hazard if used without a code-mandated thermal barrier. Insulations protected by a thermal barrier are fire safe and the use of flame retardants does not provide any additional benefit. Evidence is examined of the health and ecological impacts from the added flame-retardant chemicals. Changing the building codes could prevent health and environmental harm from the toxicity of these substances without a reduction in fire safety. Plastic foam insulations that are protected by a thermal barrier should be exempted from the Steiner Tunnel test and the need to use flame retardants. This change would align US codes with code regulations in Sweden and Norway and ensure the fire safety as well as improve health and environmental impacts.

Les codes de construction américains prennent en compte de manière équilibrée les dangers pour la sécurité publique, la santé et le bien-être général. Les codes actuels exigent que les matériaux d'isolation en mousse de plastique possèdent à la fois une protection assurée par une barrière thermique et une conformité aux exigences des tests en tunnel Steiner. Il est satisfait à l'essai en tunnel Steiner par l'ajout à la mousse de produits chimiques retardateurs de flamme. Les études démontrent que l'essai en tunnel Steiner ne donne pas de résultats fiables en matière de sécurité incendie concernant les isolations en mousse de plastique. Les mousses qui satisfont à cet essai présentent encore un risque incendie en cas d'utilisation sans une barrière thermique prescrite par un code. Les isolations protégées par une barrière thermique sont ignifuges et l'utilisation de retardateurs de flamme n'apporte aucun avantage supplémentaire. Sont examinés les éléments probants relatifs aux incidences sur la santé et l'environnement des produits chimiques retardateurs de flamme qui sont ajoutés. La modification des codes de construction pourrait prévenir les dommages en matière de santé et d'environnement dus à la toxicité de ces substances sans réduction de la sécurité incendie. Les isolations en mousse de plastique qui sont protégées par une barrière thermique devraient être dispensées de l'essai en tunnel Steiner et de la nécessité d'utiliser des retardateurs de flamme. Ce changement alignerait les codes américains sur les règles des codes en vigueur en Suède et en Norvège et garantirait la sécurité incendie tout en améliorant les incidences sur la santé et l'environnement.

Mots clés: codes de construction?sécurité incendie?retardateurs de flamme?inflammabilité?isolation?santé publique?Tunnel Steiner?barrière thermique?toxicité     

The interorganizational innovation processes of sustainable building: A Dutch case of joint building innovation in sustainability

This article's subject is the cooperation process between organizations that develop and implement innovations in sustainable building. Its main research question is how governmental and commercial organizations organize and structure their joint activities to develop innovations in sustainability. In the search for answers to this question the cooperative activities of innovating organizations are modelled as an interorganizational innovation process. The case study research method is used to investigate the development of interorganizational innovation patterns in sustainability in seven house-building projects in the Dutch residential building sector. The empirical research findings are discussed by means of a comparison with the theoretical framework that includes five complementary stage models of interorganizational innovation processes. The main conclusions of the research are that (1) governmental and commercial organizations that successfully innovate in sustainability go through eight consecutive stages of interorganizational innovation, and (2) perform twenty-two interaction patterns that are part of these stages.     

住区建成环境对老年人生活品质影响的实证研究 ——以大连市既有住区为例

伴随着生活圈的不断收缩,住区逐渐成 为了老年人日常生活的主要场所,然而,既有住区 的建成环境却往往不能满足老年人生活需求, 影响老年人的生活品质。研究以大连市既有住区 建成环境为对象,基于扎根理论采用拍照、测 绘、半开放式访谈的方法,结合文献梳理,分析 了住区建成环境对老年人生活品质的影响。研究 认为住区建成环境现状问题主要体现于无障碍 设计缺失、规划缺失以及管理缺失。这些问题均 导致了老年人生活品质下降,且主要体现于无法 满足营养需求、安全感需求、卫生需求以及社交 需求。因此,为了提高老年人的生活品质,在进行 建成环境改造时,应该充分考虑导致老年人生 活品质下降背后的动因,并以需求为导向进行统 筹优化。研究认为老年人生活品质是一项综合的指标,通过建成环境的优化能够在一定程度上对其进行提升,但只有建成环境与社会环境协同作 用,才能更有效的提升老年人的生活品质。     

Feasibility of zero carbon homes in England by 2016: A house builder's perspective

The UK government set itself a 60% reduction of carbon dioxide emissions target on 2000 levels by 2050. This commitment will require carbon reductions to be made by all industries including the housing sector which presently accounts for 27% of carbon dioxide emissions. The house building industry is the subject of numerous government policies and legislation, but none are as demanding as the Code of Sustainable Homes, which set a ‘world-beating’ target for all new homes to be zero carbon by 2016. This paper sets out to investigate the feasibility of building zero carbon homes in England by 2016 from a house builder's perspective. A comprehensive opinion of the feasibility of zero carbon homes is gathered through a questionnaire survey and in-depth semi-structured interviews with the major UK housing developers. The research found that there are currently numerous legislative, cultural, financial and technical barriers facing house builders to deliver zero carbon homes in England by 2016. The house builders surveyed concurred that these challenges are not insurmountable provided that a swift, all-embracing and above all realistic strategy is adopted and implemented across the supply chain.