101
|
Padhi BK, Adhikari A, Satapathy P, Patra AK, Chandel D, Panigrahi P. Predictors and respiratory depositions of airborne endotoxin in homes using biomass fuels and LPG gas for cooking. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2017; 27:112-117. [PMID: 26956936 PMCID: PMC5017895 DOI: 10.1038/jes.2016.5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 11/28/2015] [Indexed: 05/30/2023]
Abstract
Recent studies have highlighted the presence of endotoxin in indoor air and its role in respiratory morbidities. Burning of household fuels including unprocessed wood and dried animal dung could be a major source of endotoxin in homes. We measured endotoxin levels in different size fractions of airborne particles (PM10, PM2.5, and PM1), and estimated the deposition of particle-bound endotoxin in the respiratory tract. The study was carried out in homes burning solid biomass fuel (n=35) and LPG (n=35). Sample filters were analyzed for endotoxin and organic carbon (OC) content. Household characteristics including temperature, relative humidity, and carbon dioxide levels were also recorded. Multivariate regression models were used to estimate the contributing factors for airborne endotoxin. Respiratory deposition doses were calculated using a computer-based model. We found a higher endotoxin concentration in PM2.5 fractions of the particle in both LPG (median: 110, interquartile range (IQR) 100-120 EU/m3) and biomass (median: 350, IQR: 315-430 EU/m3) burning homes. In the multivariate-adjusted model, burning of solid biomass fuel (β: 67; 95% CI: 10.5-124) emerged as the most significant predictor followed by OC (β: 4.7; 95% CI: 2.7-6.8), RH (β: 1.6; 95% CI: 0.76-2.4), and PM2.5 (β: 0.45; 95% CI: 0.11-0.78) for airborne endotoxin (P<0.05). We also observed an interaction between PM organic carbon content and household fuel in predicting the endotoxin levels. The model calculations showed that in biomass burning homes, total endotoxin deposition was higher among infants (59%) than in adult males (47%), of which at least 10% of inhaled endotoxin is deposited in the alveolar region of the lung. These results indicate that fine particles are significant contributors to the deposition of endotoxin in the alveolar region of the lung. Considering the paramount role of endotoxin exposure, and the source and timing of exposure on respiratory health, additional studies are warranted to guide evidence-based public health interventions.
Collapse
Affiliation(s)
- Bijaya Kumar Padhi
- Center for Environmental and Occupational Health, Asian Institute of Public Health, Bhubaneswar, India
| | - Atin Adhikari
- Department of Environmental Health Sciences, Jiann-Ping Hsu College of Public Health, Georgia Southern University, PO Box 8015, Statesboro, Georgia 30460, USA
| | - Prakasini Satapathy
- Department of Biotechnology, Ravenshaw University, Cuttack, India
- Regional Medical Research Center, Bhubaneswar, Indian Council of Medical Research, Odisha, India
| | - Alok Kumar Patra
- Center for Global Health and Development, College of Public Health, University of Nebraska Medical Center, USA
| | - Dinesh Chandel
- Center for Global Health and Development, College of Public Health, University of Nebraska Medical Center, USA
| | - Pinaki Panigrahi
- Center for Global Health and Development, College of Public Health, University of Nebraska Medical Center, USA
| |
Collapse
|
102
|
Hoisington A, Maestre JP, Kinney KA, Siegel JA. Characterizing the bacterial communities in retail stores in the United States. INDOOR AIR 2016; 26:857-868. [PMID: 26610179 DOI: 10.1111/ina.12273] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Accepted: 11/17/2015] [Indexed: 05/03/2023]
Abstract
The microorganisms present in retail environments have not been studied in detail despite the fact that these environments represent a potentially important location for exposure. In this study, HVAC filter dust samples in 13 US retail stores were collected and analyzed via pyrosequencing to characterize the indoor bacterial communities and to explore potential relationships between these communities and building and environmental parameters. Although retail stores contained a diverse bacterial community of 788 unique genera, over half of the nearly 118K sequences were attributed to the Proteobacteria phylum. Streptophyta, Bacillus, Corynebacterium, Pseudomonas, and Acinetobacter were the most prevalent genera detected. The recovered indoor airborne microbial community was statistically associated with both human oral and skin microbiota, indicating occupants are important contributors, despite a relatively low occupant density per unit volume in retail stores. Bacteria generally associated with outdoor environments were present in the indoor communities with no obvious association with air exchange rate, even when considering relative abundance. No significant association was observed between the indoor bacterial community recovered and store location, store type, or season. However, predictive functional gene profiling showed significant associations between the indoor community and season. The microbiome recovered from multiple samples collected months apart from the same building varied significantly indicating that caution is warranted when trying to characterize the bacterial community with a single sampling event.
Collapse
Affiliation(s)
- A Hoisington
- Department of Civil and Environmental Engineering, The United States Air Force Academy, Colorado Springs, CO, USA
| | - J P Maestre
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, Austin, TX, USA
| | - K A Kinney
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, Austin, TX, USA
| | - J A Siegel
- Department of Civil Engineering, University of Toronto, Toronto, ON, Canada
- Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
103
|
Stamper CE, Hoisington AJ, Gomez OM, Halweg-Edwards AL, Smith DG, Bates KL, Kinney KA, Postolache TT, Brenner LA, Rook GAW, Lowry CA. The Microbiome of the Built Environment and Human Behavior: Implications for Emotional Health and Well-Being in Postmodern Western Societies. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2016; 131:289-323. [PMID: 27793224 DOI: 10.1016/bs.irn.2016.07.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
It is increasingly evident that inflammation is an important determinant of cognitive function and emotional behaviors that are dysregulated in stress-related psychiatric disorders, such as anxiety and affective disorders. Inflammatory responses to physical or psychological stressors are dependent on immunoregulation, which is indicated by a balanced expansion of effector T-cell populations and regulatory T cells. This balance is in part driven by microbial signals. The hygiene or "old friends" hypothesis posits that exposure to immunoregulation-inducing microorganisms is reduced in modern urban societies, leading to an epidemic of inflammatory disease and increased vulnerability to stress-related psychiatric disorders. With the global trend toward urbanization, humans are progressively spending more time in built environments, thereby, experiencing limited exposures to these immunoregulatory "old friends." Here, we evaluate the implications of the global trend toward urbanization, and how this transition may affect human microbial exposures and human behavior.
Collapse
Affiliation(s)
- C E Stamper
- Center for Neuroscience, University of Colorado Boulder, Boulder, CO, United States
| | - A J Hoisington
- US Air Force Academy, Colorado Springs, CO, United States; Military and Veteran Microbiome Consortium for Research and Education (MVM-CoRE), Denver, CO, United States
| | - O M Gomez
- Center for Neuroscience, University of Colorado Boulder, Boulder, CO, United States
| | | | - D G Smith
- Center for Neuroscience, University of Colorado Boulder, Boulder, CO, United States
| | - K L Bates
- US Air Force Academy, Colorado Springs, CO, United States
| | - K A Kinney
- Military and Veteran Microbiome Consortium for Research and Education (MVM-CoRE), Denver, CO, United States; University of Texas Austin, Austin, TX, United States
| | - T T Postolache
- Military and Veteran Microbiome Consortium for Research and Education (MVM-CoRE), Denver, CO, United States; University of Maryland School of Medicine, Baltimore, MD, United States; VISN 5 Mental Illness Research Education and Clinical Center (MIRECC), Baltimore, MD, United States; Rocky Mountain Mental Illness Research Education and Clinical Center, Denver, CO, United States
| | - L A Brenner
- Military and Veteran Microbiome Consortium for Research and Education (MVM-CoRE), Denver, CO, United States; Rocky Mountain Mental Illness Research Education and Clinical Center, Denver, CO, United States; University of Colorado, Aurora, CO, United States
| | - G A W Rook
- Center for Clinical Microbiology, UCL (University College London), London, United Kingdom
| | - C A Lowry
- Center for Neuroscience, University of Colorado Boulder, Boulder, CO, United States; Military and Veteran Microbiome Consortium for Research and Education (MVM-CoRE), Denver, CO, United States; Rocky Mountain Mental Illness Research Education and Clinical Center, Denver, CO, United States; University of Colorado, Aurora, CO, United States.
| |
Collapse
|
104
|
Thomassen MR, Kamath SD, Lopata AL, Madsen AM, Eduard W, Bang BE, Aasmoe L. Occupational Exposure to Bioaerosols in Norwegian Crab Processing Plants. ANNALS OF OCCUPATIONAL HYGIENE 2016; 60:781-94. [DOI: 10.1093/annhyg/mew030] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 05/03/2016] [Indexed: 12/30/2022]
|
105
|
Characteristics of pathogenic microorganisms found in 99 cases of conjunctivitis from the Qinghai Tibetan area. SCIENCE CHINA. LIFE SCIENCES 2016; 59:571-2. [PMID: 27225261 DOI: 10.1007/s11427-016-5061-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 04/08/2016] [Indexed: 10/21/2022]
|
106
|
Leung MHY, Lee PKH. The roles of the outdoors and occupants in contributing to a potential pan-microbiome of the built environment: a review. MICROBIOME 2016; 4:21. [PMID: 27216717 PMCID: PMC4877933 DOI: 10.1186/s40168-016-0165-2] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 04/11/2016] [Indexed: 05/10/2023]
Abstract
Recent high-throughput sequencing technology has led to an expansion of knowledge regarding the microbial communities (microbiome) across various built environments (BEs). The microbiome of the BE is dependent upon building factors and conditions that govern how outdoor microbes enter and persist in the BE. Additionally, occupants are crucial in shaping the microbiome of the BE by releasing human-associated microorganisms and resuspending microbes on floors and surfaces. Therefore, both the outdoors and occupants act as major sources of microorganisms found in the BE. However, most characterizations of the microbiome of the BE have been conducted in the Western world. Notably, outdoor locations and population groups present geographical variations in outdoor and human microbiomes, respectively. Given the influences of the outdoor and human microbiomes on BE microbiology, and the geographical variations in outdoor and human microbiomes, it is likely that the microbiomes of BEs also vary by location. The summation of microbiomes between BEs contribute to a potential BE pan-microbiome, which will both consist of microbes that are ubiquitous in indoor environments around the world, and microbes that appear to be endemic to particular geographical locations. Importantly, the BE pan-microbiome can potentially question the global application of our current views on indoor microbiology. In this review, we first provide an assessment on the roles of building and occupant properties on shaping the microbiome of the BE. This is then followed by a description of geographical variations in the microbiomes of the outdoors and humans, the two main sources of microbes in BEs. We present evidence of differences in microbiomes of BEs around the world, demonstrating the existence of a global pan-microbiome of the BE that is larger than the microbiome of any single indoor environment. Finally, we discuss the significance of understanding the BE pan-microbiome and identifying universal and location-specific relationships between building and occupant characteristics and indoor microbiology. This review highlights the much needed efforts towards determining the pan-microbiome of the BE, thereby identifying general and location-specific links between the microbial communities of the outdoors, human, and BE ecosystems, ultimately improving the health, comfort, and productivity of occupants around the world.
Collapse
Affiliation(s)
- Marcus H. Y. Leung
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, B5423-AC1 Hong Kong
| | - Patrick K. H. Lee
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, B5423-AC1 Hong Kong
| |
Collapse
|
107
|
Madsen AM, Alwan T, Ørberg A, Uhrbrand K, Jørgensen MB. Waste Workers’ Exposure to Airborne Fungal and Bacterial Species in the Truck Cab and During Waste Collection. ANNALS OF OCCUPATIONAL HYGIENE 2016; 60:651-68. [PMID: 27098185 PMCID: PMC4915520 DOI: 10.1093/annhyg/mew021] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/15/2016] [Indexed: 12/30/2022]
Abstract
A large number of people work with garbage collection, and exposure to microorganisms is considered an occupational health problem. However, knowledge on microbial exposure at species level is limited. The aim of the study was to achieve knowledge on waste collectors’ exposure to airborne inhalable fungal and bacterial species during waste collection with focus on the transport of airborne microorganisms into the truck cab. Airborne microorganisms were collected with samplers mounted in the truck cab, on the workers’ clothes, and outdoors. Fungal and bacterial species were quantified and identified. The study showed that the workers were exposed to between 112 and 4.8×104 bacteria m−3 air and 326 and 4.6×104 fungi m−3 air. The personal exposures to bacteria and fungi were significantly higher than the concentrations measured in the truck cabs and in the outdoor references. On average, the fungal and bacterial concentrations in truck cabs were 111 and 7.7 times higher than outdoor reference measurements. In total, 23 fungal and 38 bacterial species were found and identified. Most fungal species belonged to the genus Penicillium and in total 11 Penicillium species were found. Identical fungal species were often found both in a personal sample and in the same person’s truck cab, but concentrations were on average 27 times higher in personal samples. Concentrations of fungal and bacterial species found only in the personal samples were lower than concentrations of species also found in truck cabs. Skin-related bacteria constituted a large fraction of bacterial isolates found in personal and truck cab samples. In total, six Staphylococcus species were found. In outdoor samples, no skin-related bacteria were found. On average, concentrations of bacterial species found both in the truck cab and personal samples were 77 times higher in personal samples than in truck cab samples. In conclusion, high concentrations of fungi were found in truck cabs, but the highest concentrations were found in personal samples; fungal and bacterial species found in high concentrations in personal samples were also found in truck cabs, but in lower concentrations indicating that both fungi and bacteria are transported by the workers into the truck cab, and are subsequently aerosolized in the truck cab.
Collapse
Affiliation(s)
- Anne Mette Madsen
- The National Research Centre for the Working Environment, Lersø Parkallé 105, DK-2100 Copenhagen Ø, Denmark
| | - Taif Alwan
- The National Research Centre for the Working Environment, Lersø Parkallé 105, DK-2100 Copenhagen Ø, Denmark
| | - Anders Ørberg
- The National Research Centre for the Working Environment, Lersø Parkallé 105, DK-2100 Copenhagen Ø, Denmark
| | - Katrine Uhrbrand
- The National Research Centre for the Working Environment, Lersø Parkallé 105, DK-2100 Copenhagen Ø, Denmark
| | - Marie Birk Jørgensen
- The National Research Centre for the Working Environment, Lersø Parkallé 105, DK-2100 Copenhagen Ø, Denmark
| |
Collapse
|
108
|
Generation and Characterization of Indoor Fungal Aerosols for Inhalation Studies. Appl Environ Microbiol 2016; 82:2479-93. [PMID: 26921421 PMCID: PMC4959492 DOI: 10.1128/aem.04063-15] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 02/01/2016] [Indexed: 12/11/2022] Open
Abstract
In the indoor environment, people are exposed to several fungal species. Evident dampness is associated with increased respiratory symptoms. To examine the immune responses associated with fungal exposure, mice are often exposed to a single species grown on an agar medium. The aim of this study was to develop an inhalation exposure system to be able to examine responses in mice exposed to mixed fungal species aerosolized from fungus-infested building materials. Indoor airborne fungi were sampled and cultivated on gypsum boards. Aerosols were characterized and compared with aerosols in homes. Aerosols containing 107 CFU of fungi/m3 air were generated repeatedly from fungus-infested gypsum boards in a mouse exposure chamber. Aerosols contained Aspergillus nidulans, Aspergillus niger, Aspergillus ustus, Aspergillus versicolor, Chaetomium globosum, Cladosporiumherbarum, Penicillium brevicompactum, Penicillium camemberti, Penicillium chrysogenum, Penicillium commune, Penicillium glabrum, Penicillium olsonii, Penicillium rugulosum, Stachybotrys chartarum, and Wallemia sebi. They were all among the most abundant airborne species identified in 28 homes. Nine species from gypsum boards and 11 species in the homes are associated with water damage. Most fungi were present as single spores, but chains and clusters of different species and fragments were also present. The variation in exposure level during the 60 min of aerosol generation was similar to the variation measured in homes. Through aerosolization of fungi from the indoor environment, cultured on gypsum boards, it was possible to generate realistic aerosols in terms of species composition, concentration, and particle sizes. The inhalation-exposure system can be used to study responses to indoor fungi associated with water damage and the importance of fungal species composition.
Collapse
|
109
|
Ramsay KA, Stockwell RE, Bell SC, Kidd TJ. Infection in cystic fibrosis: impact of the environment and climate. Expert Rev Respir Med 2016; 10:505-19. [PMID: 26949990 DOI: 10.1586/17476348.2016.1162715] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In many countries numbers of adults with cystic fibrosis (CF) exceed that of children, with median survival predicted to surpass 50 years. Increasing longevity is, in part, due to intensive therapies including eradication of early infection and suppressive therapies and pulmonary exacerbations. Initial infections with common CF pathogens are thought to arise from the natural environment. We review the impact of climate and environment on infection in CF. Specifically, several studies indicate that higher ambient temperatures, proximity to the equator and the summer season may be linked to the increased prevalence of Pseudomonas aeruginosa in people with CF. The environment may also play an important role in the acquisition of Gram negative organisms other than P. aeruginosa. There is emerging data suggesting that climatic and environmental factors are likely to impact on the risk of infection with NTM and fungi in people which are found extensively throughout the natural environment.
Collapse
Affiliation(s)
- K A Ramsay
- a Lung Bacteria Group , QIMR Berghofer Medical Research Institute , Brisbane , Australia.,b Child Health Research Centre, The University of Queensland , Brisbane , Australia.,c School of Medicine , The University of Queensland , Brisbane , Australia
| | - R E Stockwell
- a Lung Bacteria Group , QIMR Berghofer Medical Research Institute , Brisbane , Australia
| | - S C Bell
- a Lung Bacteria Group , QIMR Berghofer Medical Research Institute , Brisbane , Australia.,c School of Medicine , The University of Queensland , Brisbane , Australia.,d Adult Cystic Fibrosis Centre , The Prince Charles Hospital , Brisbane , Australia
| | - T J Kidd
- b Child Health Research Centre, The University of Queensland , Brisbane , Australia.,e Centre for Infection and Immunity , Queen's University Belfast , Belfast , UK.,f School of Chemistry and Molecular Biosciences , The University of Queensland , Brisbane , Australia
| |
Collapse
|
110
|
Abstract
A gathering body of evidence has repeatedly revealed associations between indoor fungi and initiation, promotion, and exacerbation of allergic respiratory disease. The relationship between the exposure and outcome are complicated by the difficulties in measuring both exposure and outcome, the multifactorial nature of the disease, and the wide range of potential confounders. New technologies are becoming available that may enable better measurement of exposure and tighter case definitions so as to build more confidence in the associations discovered. The growing strength of the evidence base will aid the design of future public health interventions and generate new hypotheses on the cause of the rapid increase in allergic respiratory disease prevalence.
Collapse
|
111
|
Hwang SH, Park DJ, Park WM, Park DU, Ahn JK, Yoon CS. Seasonal variation in airborne endotoxin levels in indoor environments with different micro-environmental factors in Seoul, South Korea. ENVIRONMENTAL RESEARCH 2016; 145:101-108. [PMID: 26656510 DOI: 10.1016/j.envres.2015.11.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 11/18/2015] [Accepted: 11/20/2015] [Indexed: 06/05/2023]
Abstract
This study evaluated the variation over a year in airborne endotoxin levels in the indoor environment of five university laboratories in Seoul, South Korea, and examined the micro-environmental factors that influenced endotoxin levels. These included temperature, relative humidity, CO2, CO, illumination, and wind velocity. A total of 174 air samples were collected and analyzed using the kinetic limulus amebocyte lysate assay. Endotoxin levels ranged from <0.001 to 8.90EU/m(3), with an overall geometric mean of 0.240EU/m(3). Endotoxin levels showed significantly negative correlation with temperature (r=-0.529, p<0.001), CO2 (r=-0.213, p<0.001) and illumination (r=-0.538, p<0.001). Endotoxin levels tended to be higher in winter. Endotoxin levels in laboratories with rabbits were significantly higher than those of laboratories with mice. Multivariate regression analysis showed that the environmental factors affecting endotoxin levels were temperature (coefficient=-0.388, p<0.001) and illumination (coefficient=-0.370, p<0.001). Strategies aimed at reducing airborne endotoxin levels in the indoor environments may be most effective if they focus on illumination.
Collapse
Affiliation(s)
- Sung Ho Hwang
- National Cancer Control Institute, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, South Korea
| | - Dong Jin Park
- Occupational Safety and Health Research, Ulsan, South Korea
| | - Wha Me Park
- Institute of Environmental and Industrial Medicine, Hanyang University, Seoul, South Korea
| | - Dong Uk Park
- Department of Environmental Health, Korea National Open University, Seoul, South Korea
| | - Jae Kyoung Ahn
- Research Institute of Standards for Environmental Testing, Seoul, South Korea
| | - Chung Sik Yoon
- Institute of Health and Environment, School of Public Health, Seoul National University, Gwanak ,1 Gwanak-ro, Seoul, South Korea.
| |
Collapse
|
112
|
Ruiz-Calderon JF, Cavallin H, Song SJ, Novoselac A, Pericchi LR, Hernandez JN, Rios R, Branch OH, Pereira H, Paulino LC, Blaser MJ, Knight R, Dominguez-Bello MG. Walls talk: Microbial biogeography of homes spanning urbanization. SCIENCE ADVANCES 2016; 2:e1501061. [PMID: 26933683 PMCID: PMC4758746 DOI: 10.1126/sciadv.1501061] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 11/29/2015] [Indexed: 05/24/2023]
Abstract
Westernization has propelled changes in urbanization and architecture, altering our exposure to the outdoor environment from that experienced during most of human evolution. These changes might affect the developmental exposure of infants to bacteria, immune development, and human microbiome diversity. Contemporary urban humans spend most of their time indoors, and little is known about the microbes associated with different designs of the built environment and their interaction with the human immune system. This study addresses the associations between architectural design and the microbial biogeography of households across a gradient of urbanization in South America. Urbanization was associated with households' increased isolation from outdoor environments, with additional indoor space isolation by walls. Microbes from house walls and floors segregate by location, and urban indoor walls contain human bacterial markers of space use. Urbanized spaces uniquely increase the content of human-associated microbes-which could increase transmission of potential pathogens-and decrease exposure to the environmental microbes with which humans have coevolved.
Collapse
Affiliation(s)
- Jean F. Ruiz-Calderon
- Department of Biology, University of Puerto Rico, Rio Piedras Campus, San Juan, PR 00931, USA
| | - Humberto Cavallin
- School of Architecture, University of Puerto Rico, Rio Piedras Campus, San Juan, PR 00931, USA
| | - Se Jin Song
- Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Atila Novoselac
- Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin, Austin, TX 78712, USA
| | - Luis R. Pericchi
- Department of Mathematics, University of Puerto Rico, Rio Piedras Campus, San Juan, PR 00931, USA
| | - Jean N. Hernandez
- Department of Biology, University of Puerto Rico, Rio Piedras Campus, San Juan, PR 00931, USA
| | - Rafael Rios
- Department of Environmental Sciences, University of Puerto Rico, Rio Piedras Campus, San Juan, PR 00931, USA
| | - Oralee H. Branch
- Department of Microbiology, New York University Langone Medical Center, New York, NY 10016, USA
| | | | - Luciana C. Paulino
- Center for Natural Sciences and Humanities, Federal University of ABC, Santo André, SP 09210, Brazil
| | - Martin J. Blaser
- Department of Medicine, New York University Langone Medical Center, New York, NY 10016, USA
| | - Rob Knight
- Departments of Pediatrics and Computer Science & Engineering, University of California at San Diego, La Jolla, CA 92093, USA
| | - Maria G. Dominguez-Bello
- Department of Biology, University of Puerto Rico, Rio Piedras Campus, San Juan, PR 00931, USA
- Department of Medicine, New York University Langone Medical Center, New York, NY 10016, USA
| |
Collapse
|
113
|
Normand AC, Ranque S, Cassagne C, Gaudart J, Sallah K, Charpin DA, Piarroux R. Comparison of Air Impaction and Electrostatic Dust Collector Sampling Methods to Assess Airborne Fungal Contamination in Public Buildings. ANNALS OF OCCUPATIONAL HYGIENE 2015; 60:161-75. [DOI: 10.1093/annhyg/mev075] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 09/23/2015] [Indexed: 12/30/2022]
|
114
|
Brown T, Dassonville C, Derbez M, Ramalho O, Kirchner S, Crump D, Mandin C. Relationships between socioeconomic and lifestyle factors and indoor air quality in French dwellings. ENVIRONMENTAL RESEARCH 2015; 140:385-396. [PMID: 25935319 DOI: 10.1016/j.envres.2015.04.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 04/20/2015] [Accepted: 04/21/2015] [Indexed: 06/04/2023]
Abstract
BACKGROUND To date, few studies have analyzed the relationships between socioeconomic status (SES) and indoor air quality (IAQ). OBJECTIVE The aim of this study was to examine the relationships between socioeconomic and other factors and indoor air pollutant levels in French homes. METHODS The indoor air concentrations of thirty chemical, biological and physical parameters were measured over one week in a sample of 567 dwellings representative of the French housing stock between September 2003 and December 2005. Information on SES (household structure, educational attainment, income, and occupation), building characteristics, and occupants' habits and activities (smoking, cooking, cleaning, etc.) were collected through administered questionnaires. Separate stepwise linear regression models were fitted to log-transformed concentrations on SES and other factors. Logistic regression was performed on fungal contamination data. RESULTS Households with lower income were more likely to have higher indoor concentrations of formaldehyde, but lower perchloroethylene indoor concentrations. Formaldehyde indoor concentrations were also associated with newly built buildings. Smoking was associated with increasing acetaldehyde and PM2.5 levels and the risk of a positive fungal contamination index. BTEX levels were also associated with occupant density and having an attached garage. The major predictors for fungal contamination were dampness and absolute humidity. CONCLUSION These results, obtained from a large sample of dwellings, show for the first time in France the relationships between SES factors and indoor air pollutants, and believe they should be considered alongside occupant activities and building characteristics when study IAQ in homes.
Collapse
Affiliation(s)
- Terry Brown
- Institute of Environment, Health, Risks and Futures, School of Environment, Energy & Agrifoods, Cranfield University, Cranfield, Milton Keynes, Bedfordshire MK43 0AL, UK.
| | - Claire Dassonville
- Paris-East University/Scientific and Technical Centre for Building (CSTB), Observatory on Indoor Air Quality, 84 Avenue Jean Jaurès, Champs-sur-Marne, F-77447 Marne-la-Vallée Cedex 2, France
| | - Mickael Derbez
- Paris-East University/Scientific and Technical Centre for Building (CSTB), Observatory on Indoor Air Quality, 84 Avenue Jean Jaurès, Champs-sur-Marne, F-77447 Marne-la-Vallée Cedex 2, France
| | - Olivier Ramalho
- Paris-East University/Scientific and Technical Centre for Building (CSTB), Observatory on Indoor Air Quality, 84 Avenue Jean Jaurès, Champs-sur-Marne, F-77447 Marne-la-Vallée Cedex 2, France
| | - Severine Kirchner
- Paris-East University/Scientific and Technical Centre for Building (CSTB), Observatory on Indoor Air Quality, 84 Avenue Jean Jaurès, Champs-sur-Marne, F-77447 Marne-la-Vallée Cedex 2, France
| | - Derrick Crump
- Institute of Environment, Health, Risks and Futures, School of Environment, Energy & Agrifoods, Cranfield University, Cranfield, Milton Keynes, Bedfordshire MK43 0AL, UK
| | - Corinne Mandin
- Paris-East University/Scientific and Technical Centre for Building (CSTB), Observatory on Indoor Air Quality, 84 Avenue Jean Jaurès, Champs-sur-Marne, F-77447 Marne-la-Vallée Cedex 2, France
| |
Collapse
|
115
|
Holst G, Høst A, Doekes G, Meyer HW, Madsen AM, Sigsgaard T. Determinants of house dust, endotoxin, and β-(1→3)-D-glucan in homes of Danish children. INDOOR AIR 2015; 25:245-59. [PMID: 25039673 DOI: 10.1111/ina.12143] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 07/06/2014] [Indexed: 05/24/2023]
Abstract
Little is known about the geographic variation and determinants of bacterial endotoxin and β-(1,3)-D-glucan in Danish house dust. In a population of 317 children, we: (i) described loads and concentrations of floor dust, endotoxin, and β-(1→3)-D-glucan and (ii) their correlations and (iii) assessed their determinants; (iv) Finally, we compared our findings with previous European studies. Bedroom floor dust was analyzed for endotoxin content by the kinetic limulus amoebocyte lysate assay and for β-(1→3)-D-glucan by the inhibition enzyme immunoassay. The parents answered questions regarding potential determinants. We found: geometric means (geometric standard deviations) 186 mg/m(2) (4.3) for dust; 5.46 × 10(3) EU/m(2) (8.0) and 31.1 × 10(3) EU/g (2.6) for endotoxin; and 142 μg/m(2) (14.3) and 0.71 × 10(3) μg/g (7.3) for β-(1→3)-D-glucan. High correlations (r > 0.75) were found between floor dust and endotoxin and β-(1→3)-D-glucan loads, while endotoxin and β-(1→3)-D-glucan concentrations were moderately correlated (r = 0.36-0.41) with the dust load. Having a carpet was positively associated with dust load and with endotoxin and β-(1→3)-D-glucan concentrations. Pet keeping, dwelling type, and dwelling location were determinants of endotoxin concentrations. No other determinants were associated with β-(1→3)-D-glucan concentrations. Compared with other European studies, we found lower β-(1→3)-D-glucan loads and concentrations but higher endotoxin loads and concentrations suggesting a geographically determined different composition of Danish floor dust compared with other European regions.
Collapse
Affiliation(s)
- G Holst
- Section of Environment, Occupation and Health, Aarhus University, Aarhus, Denmark
| | | | | | | | | | | |
Collapse
|
116
|
Blais-Lecours P, Perrott P, Duchaine C. Non-culturable bioaerosols in indoor settings: Impact on health and molecular approaches for detection. ATMOSPHERIC ENVIRONMENT (OXFORD, ENGLAND : 1994) 2015; 110:45-53. [PMID: 32288547 PMCID: PMC7108366 DOI: 10.1016/j.atmosenv.2015.03.039] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 03/09/2015] [Accepted: 03/19/2015] [Indexed: 05/21/2023]
Abstract
Despite their significant impact on respiratory health, bioaerosols in indoor settings remain understudied and misunderstood. Culture techniques, predominantly used for bioaerosol characterisation in the past, allow for the recovery of only a small fraction of the real airborne microbial burden in indoor settings, given the inability of several microorganisms to grow on agar plates. However, with the development of new tools to detect non-culturable environmental microorganisms, the study of bioaerosols has advanced significantly. Most importantly, these techniques have revealed a more complex bioaerosol burden that also includes non-culturable microorganisms, such as archaea and viruses. Nevertheless, air quality specialists and consultants remain reluctant to adopt these new research-developed techniques, given that there are relatively few studies found in the literature, making it difficult to find a point of comparison. Furthermore, it is unclear as to how this new non-culturable data can be used to assess the impact of bioaerosol exposure on human health. This article reviews the literature that describes the non-culturable fraction of bioaerosols, focussing on bacteria, archaea and viruses, and examines its impact on bioaerosol-related diseases. It also outlines available molecular tools for the detection and quantification of these microorganisms and states various research needs in this field.
Collapse
Affiliation(s)
- Pascale Blais-Lecours
- Centre de recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, QC, Canada
| | - Phillipa Perrott
- Centre de recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, QC, Canada
| | - Caroline Duchaine
- Centre de recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, QC, Canada
- Département de biochimie, de microbiologie et de bioinformatique, Faculté des sciences et de génie, Université Laval, Québec, QC, Canada
| |
Collapse
|
117
|
Pseudomonas putida and Pseudomonas fluorescens Species Group Recovery from Human Homes Varies Seasonally and by Environment. PLoS One 2015; 10:e0127704. [PMID: 26023929 PMCID: PMC4449118 DOI: 10.1371/journal.pone.0127704] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 04/17/2015] [Indexed: 02/03/2023] Open
Abstract
By shedding light on variation in time as well as in space, long-term biogeographic studies can help us define organisms' distribution patterns and understand their underlying drivers. Here we examine distributions of Pseudomonas in and around 15 human homes, focusing on the P. putida and P. fluorescens species groups. We describe recovery from 10,941 samples collected during up to 8 visits per home, occurring on average 2.6 times per year. We collected a mean of 141 samples per visit, from sites in most rooms of the house, from the surrounding yards, and from human and pet occupants. We recovered Pseudomonas in 9.7% of samples, with the majority of isolates being from the P. putida and P. fluorescens species groups (approximately 62% and 23% of Pseudomonas samples recovered respectively). Although representatives of both groups were recovered from every season, every house, and every type of environment sampled, recovery was highly variable across houses and samplings. Whereas recovery of P. putida group was higher in summer and fall than in winter and spring, P. fluorescens group isolates were most often recovered in spring. P. putida group recovery from soils was substantially higher than its recovery from all other environment types, while higher P. fluorescens group recovery from soils than from other sites was much less pronounced. Both species groups were recovered from skin and upper respiratory tract samples from healthy humans and pets, although this occurred infrequently. This study indicates that even species that are able to survive under a broad range of conditions can be rare and variable in their distributions in space and in time. For such groups, determining patterns and causes of stochastic and seasonal variability may be more important for understanding the processes driving their biogeography than the identity of the types of environments in which they can be found.
Collapse
|
118
|
Nevalainen A, Täubel M, Hyvärinen A. Indoor fungi: companions and contaminants. INDOOR AIR 2015; 25:125-56. [PMID: 25601374 DOI: 10.1111/ina.12182] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 12/20/2014] [Indexed: 05/21/2023]
Abstract
This review discusses the role of fungi and fungal products in indoor environments, especially as agents of human exposure. Fungi are present everywhere, and knowledge for indoor environments is extensive on their occurrence and ecology, concentrations, and determinants. Problems of dampness and mold have dominated the discussion on indoor fungi. However, the role of fungi in human health is still not well understood. In this review, we take a look back to integrate what cultivation-based research has taught us alongside more recent work with cultivation-independent techniques. We attempt to summarize what is known today and to point out where more data is needed for risk assessment associated with indoor fungal exposures. New data have demonstrated qualitative and quantitative richness of fungal material inside and outside buildings. Research on mycotoxins shows that just as microbes are everywhere in our indoor environments, so too are their metabolic products. Assessment of fungal exposures is notoriously challenging due to the numerous factors that contribute to the variation of fungal concentrations in indoor environments. We also may have to acknowledge and incorporate into our understanding the complexity of interactions between multiple biological agents in assessing their effects on human health and well-being.
Collapse
Affiliation(s)
- A Nevalainen
- Institute for Health and Welfare, Kuopio, Finland
| | | | | |
Collapse
|
119
|
Stephens B, Adams RI, Bhangar S, Bibby K, Waring MS. From commensalism to mutualism: integrating the microbial ecology, building science, and indoor air communities to advance research on the indoor microbiome. INDOOR AIR 2015; 25:1-3. [PMID: 25594131 DOI: 10.1111/ina.12167] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
|
120
|
Sharpe R, Thornton CR, Osborne NJ. Modifiable factors governing indoor fungal diversity and risk of asthma. Clin Exp Allergy 2014; 44:631-41. [PMID: 24471926 DOI: 10.1111/cea.12281] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Exposure to dampness and fungi in the home is a known risk factor for individuals with allergic asthma. Inadequate heating and ventilation may lead to dampness and concomitant increased exposure to spores of allergenic fungi such as Aspergillus and Penicillium. These fungi have been cultured from sputum of asthmatic and non-asthmatic individuals, and implicated in the initiation or exacerbation of asthma. Indoor environmental factors influence the presence and concentrations of fungal propagules and, in turn, risk of asthma outcomes. This review aims to identify modifiable risk factors in the built environment that have been shown to influence fungal composition indoors, and to examine this association with the risk of asthma development and/or exacerbation. A complex interaction between residential characteristics, the built environment and the behaviour of people regulate the diversity and concentrations of indoor fungi. Modifiable factors include build age, architectural design, level of maintenance, variations in construction materials, presence of pets, heating and ventilation patterns. Risk of fungal contamination and asthma outcomes are also influenced by low occupant awareness concerning potential health effects and socio-economic factors. Addressing these factors provides an opportunity to improve future housing interventions, though it is not clear how the built environment and occupant behaviours interact to modify the diversity of indoor fungi and resultant risk of asthma. A combination of housing improvements combined with awareness programmes and the alleviation of fuel poverty can be used to lower the allergen burden associated with damp homes. Further research is needed to identify factors that regulate the concentration and diversity of indoor fungi and how this may act as a modifier for asthma outcomes.
Collapse
Affiliation(s)
- R Sharpe
- European Centre for Environment and Human Health, University of Exeter Medical School, Truro, UK
| | | | | |
Collapse
|
121
|
Karottki DG, Bekö G, Clausen G, Madsen AM, Andersen ZJ, Massling A, Ketzel M, Ellermann T, Lund R, Sigsgaard T, Møller P, Loft S. Cardiovascular and lung function in relation to outdoor and indoor exposure to fine and ultrafine particulate matter in middle-aged subjects. ENVIRONMENT INTERNATIONAL 2014; 73:372-81. [PMID: 25233101 DOI: 10.1016/j.envint.2014.08.019] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 08/11/2014] [Accepted: 08/31/2014] [Indexed: 05/22/2023]
Abstract
This cross-sectional study investigated the relationship between exposure to airborne indoor and outdoor particulate matter (PM) and cardiovascular and respiratory health in a population-based sample of 58 residences in Copenhagen, Denmark. Over a 2-day period indoor particle number concentrations (PNC, 10-300 nm) and PM2.5 (aerodynamic diameter<2.5 μm) were monitored for each of the residences in the living room, and outdoor PNC (10-280 nm), PM2.5 and PM10 (aerodynamic diameter<10 μm) were monitored at an urban background station in Copenhagen. In the morning, after the 2-day monitoring period, we measured microvascular function (MVF) and lung function and collected blood samples for biomarkers related to inflammation, in 78 middle-aged residents. Bacteria, endotoxin and fungi were analyzed in material from electrostatic dust fall collectors placed in the residences for 4 weeks. Data were analyzed using linear regression with the generalized estimating equation approach. Statistically significant associations were found between indoor PNC, dominated by indoor use of candles, and lower lung function, the prediabetic marker HbA1c and systemic inflammatory markers observed as changes in leukocyte differential count and expression of adhesion markers on monocytes, whereas C-reactive protein was significantly associated with indoor PM2.5. The presence of indoor endotoxin was associated with lower lung function and expression of adhesion markers on monocytes. An inverse association between outdoor PNC and MVF was also statistically significant. The study suggests that PNC in the outdoor environment may be associated with decreased MVF, while PNC, mainly driven by candle burning, and bioaerosols in the indoor environment may have a negative effect on lung function and markers of systemic inflammation and diabetes.
Collapse
Affiliation(s)
- Dorina Gabriela Karottki
- Department of Public Health, University of Copenhagen, Øster Farimagsgade 5, 1014 Copenhagen K, Denmark
| | - Gabriel Bekö
- International Centre for Indoor Environment and Energy, Dept. of Civil Engineering, Technical University of Denmark, Nils Koppels Allé 402, 2800 Lyngby, Denmark
| | - Geo Clausen
- International Centre for Indoor Environment and Energy, Dept. of Civil Engineering, Technical University of Denmark, Nils Koppels Allé 402, 2800 Lyngby, Denmark
| | - Anne Mette Madsen
- National Research Centre for the Working Environment, Lersø Parkallé 105, 2100 Copenhagen O, Denmark
| | - Zorana Jovanovic Andersen
- Department of Public Health, University of Copenhagen, Øster Farimagsgade 5, 1014 Copenhagen K, Denmark
| | - Andreas Massling
- Department of Environmental Science, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Matthias Ketzel
- Department of Environmental Science, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Thomas Ellermann
- Department of Environmental Science, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Rikke Lund
- Department of Public Health, University of Copenhagen, Øster Farimagsgade 5, 1014 Copenhagen K, Denmark; Center for Healthy Aging, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | - Torben Sigsgaard
- Department of Public Health - Section of Environment, Occupation and Health, Aarhus University, Bartholins Allé 2, 8000 Aarhus C, Denmark
| | - Peter Møller
- Department of Public Health, University of Copenhagen, Øster Farimagsgade 5, 1014 Copenhagen K, Denmark
| | - Steffen Loft
- Department of Public Health, University of Copenhagen, Øster Farimagsgade 5, 1014 Copenhagen K, Denmark.
| |
Collapse
|
122
|
Heo KJ, Kim HB, Lee BU. Concentration of environmental fungal and bacterial bioaerosols during the monsoon season. JOURNAL OF AEROSOL SCIENCE 2014; 77:31-37. [PMID: 32226125 PMCID: PMC7094607 DOI: 10.1016/j.jaerosci.2014.07.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 06/24/2014] [Accepted: 07/05/2014] [Indexed: 05/22/2023]
Abstract
Rain has been known to remove aerosol particles in air environments. The aerosol particles were captured and removed from the air by rain and the concentration of aerosol particles significantly decreased after rain events. Therefore, rain is regarded as having a good effect on air environments in terms of the respiratory health of the general public. However, humid environments produced by long-term rain events such a monsoon may be a sufficient condition for the growth of microorganisms and vibrations because of the splashing of droplets may facilitate the aerosolization of ground microorganisms. We therefore hypothesize that the rain may increase concentrations of bioaerosols in outdoor air environments, thereby possibly influencing respiratory diseases. To verify this hypothesis, at the initial stepwise approach, we measured the concentration of airborne biological particles before, after, and during rain in a monsoon season. The measurement data of the concentration of fungal particles and bacterial particles show quantitatively that the bioaerosol concentrations during the rain event are several times higher than the concentration of the bioaerosols in the condition of no rain.
Collapse
Affiliation(s)
- Ki Joon Heo
- Aerosol and Bioengineering Laboratory, Department of Mechanical Engineering, College of Engineering, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Hannah Bae Kim
- Aerosol and Bioengineering Laboratory, Department of Mechanical Engineering, College of Engineering, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
- Department of Mechanical Engineering, Seattle Pacific University, 3307, 3rd Avenue West, Seattle, WA 98119-1997, United States
| | - Byung Uk Lee
- Aerosol and Bioengineering Laboratory, Department of Mechanical Engineering, College of Engineering, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
- Corresponding author. Tel.: +82 2 450 4091; fax: +82 2 447 5886.
| |
Collapse
|
123
|
Indoor-air microbiome in an urban subway network: diversity and dynamics. Appl Environ Microbiol 2014; 80:6760-70. [PMID: 25172855 DOI: 10.1128/aem.02244-14] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Subway systems are indispensable for urban societies, but microbiological characteristics of subway aerosols are relatively unknown. Previous studies investigating microbial compositions in subways employed methodologies that underestimated the diversity of microbial exposure for commuters, with little focus on factors governing subway air microbiology, which may have public health implications. Here, a culture-independent approach unraveling the bacterial diversity within the urban subway network in Hong Kong is presented. Aerosol samples from multiple subway lines and outdoor locations were collected. Targeting the 16S rRNA gene V4 region, extensive taxonomic diversity was found, with the most common bacterial genera in the subway environment among those associated with skin. Overall, subway lines harbored different phylogenetic communities based on α- and β-diversity comparisons, and closer inspection suggests that each community within a line is dependent on architectural characteristics, nearby outdoor microbiomes, and connectedness with other lines. Microbial diversities and assemblages also varied depending on the day sampled, as well as the time of day, and changes in microbial communities between peak and nonpeak commuting hours were attributed largely to increases in skin-associated genera in peak samples. Microbial diversities within the subway were influenced by temperature and relative humidity, while carbon dioxide levels showed a positive correlation with abundances of commuter-associated genera. This Hong Kong data set and communities from previous studies conducted in the United States formed distinct community clusters, indicating that additional work is required to unravel the mechanisms that shape subway microbiomes around the globe.
Collapse
|
124
|
Sharpe RA, Bearman N, Thornton CR, Husk K, Osborne NJ. Indoor fungal diversity and asthma: a meta-analysis and systematic review of risk factors. J Allergy Clin Immunol 2014; 135:110-22. [PMID: 25159468 DOI: 10.1016/j.jaci.2014.07.002] [Citation(s) in RCA: 177] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 06/06/2014] [Accepted: 07/01/2014] [Indexed: 11/30/2022]
Abstract
BACKGROUND Indoor dampness increases the risk of indoor fungal growth. A complex interaction between occupant behaviors and the built environment are thought to affect indoor fungal concentrations and species diversity, which are believed to increase the risk of having asthma, exacerbation of asthma symptoms, or both. To date, no systematic review has investigated this relationship. OBJECTIVE This review aims to assess the relationship between exposure to indoor fungi identified to the genera or species level on asthma outcomes in children and adults. METHODS Ten databases were systematically searched on April 18, 2013, and limited to articles published since 1990. Reference lists were independently screened by 2 reviewers, and authors were contacted to identify relevant articles. Data were extracted from included studies meeting our eligibility criteria by 2 reviewers and quality assessed by using the Newcastle-Ottawa scale designed for assessment of case-control and cohort studies. RESULTS Cladosporium, Alternaria, Aspergillus, and Penicillium species were found to be present in higher concentrations in homes of asthmatic participants. Exposure to Penicillium, Aspergillus, and Cladosporium species were found to be associated with increased risk of reporting asthma symptoms by a limited number of studies. The presence of Cladosporium, Alternaria, Aspergillus, and Penicillium species increased the exacerbation of current asthma symptoms by 36% to 48% compared with those exposed to lower concentrations of these fungi, as shown by using random-effect estimates. Studies were of medium quality and showed medium-high heterogeneity, but evidence concerning the specific role of fungal species was limited. CONCLUSION Longitudinal studies assessing increased exposure to indoor fungi before the development of asthma symptoms suggests that Penicillium, Aspergillus, and Cladosporium species pose a respiratory health risk in susceptible populations. Increased exacerbation of current asthma symptoms in children and adults were associated with increased levels of Penicillium, Aspergillus, Cladosporium, and Alternaria species, although further work should consider the role of fungal diversity and increased exposure to other fungal species.
Collapse
Affiliation(s)
- Richard A Sharpe
- European Centre for Environment and Human Health, University of Exeter Medical School, Truro, United Kingdom
| | - Nick Bearman
- European Centre for Environment and Human Health, University of Exeter Medical School, Truro, United Kingdom; Department of Geography and Planning, University of Liverpool, Liverpool, United Kingdom
| | - Christopher R Thornton
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Kerryn Husk
- European Centre for Environment and Human Health, University of Exeter Medical School, Truro, United Kingdom
| | - Nicholas J Osborne
- European Centre for Environment and Human Health, University of Exeter Medical School, Truro, United Kingdom; Department of Paediatrics, University of Melbourne, Melbourne, Australia.
| |
Collapse
|
125
|
He C, Salonen H, Ling X, Crilley L, Jayasundara N, Cheung HC, Hargreaves M, Huygens F, Knibbs LD, Ayoko GA, Morawska L. The impact of flood and post-flood cleaning on airborne microbiological and particle contamination in residential houses. ENVIRONMENT INTERNATIONAL 2014; 69:9-17. [PMID: 24785990 DOI: 10.1016/j.envint.2014.04.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 03/27/2014] [Accepted: 04/02/2014] [Indexed: 05/26/2023]
Abstract
In January 2011, Brisbane, Australia, experienced a major river flooding event. We aimed to investigate its effects on air quality and assess the role of prompt cleaning activities in reducing the airborne exposure risk. A comprehensive, multi-parameter indoor and outdoor measurement campaign was conducted in 41 residential houses, 2 and 6 months after the flood. The median indoor air concentrations of supermicrometer particle number (PN), PM10, fungi and bacteria 2 months after the flood were comparable to those previously measured in Brisbane. These were 2.88 p cm(-3), 15 μg m(-3), 804 cf um(-3) and 177 cf um(-3) for flood-affected houses (AFH), and 2.74 p cm(-3), 15 μg m(-3), 547 cf um(-3) and 167 cf um(-3) for non-affected houses (NFH), respectively. The I/O (indoor/outdoor) ratios of these pollutants were 1.08, 1.38, 0.74 and 1.76 for AFH and 1.03, 1.32, 0.83 and 2.17 for NFH, respectively. The average of total elements (together with transition metals) in indoor dust was 2296 ± 1328 μg m(-2) for AFH and 1454 ± 678 μg m(-2) for NFH, respectively. In general, the differences between AFH and NFH were not statistically significant, implying the absence of a measureable effect on air quality from the flood. We postulate that this was due to the very swift and effective cleaning of the flooded houses by 60,000 volunteers. Among the various cleaning methods, the use of both detergent and bleach was the most efficient at controlling indoor bacteria. All cleaning methods were equally effective for indoor fungi. This study provides quantitative evidence of the significant impact of immediate post-flood cleaning on mitigating the effects of flooding on indoor bioaerosol contamination and other pollutants.
Collapse
Affiliation(s)
- Congrong He
- International Laboratory for Air Quality and Health, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, Queensland 4001, Australia
| | - Heidi Salonen
- International Laboratory for Air Quality and Health, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, Queensland 4001, Australia; Developing Indoor Environments, Finnish Institute of Occupational Health (FIOH), Topeliuksenkatu 41 aA, FI-00250 Helsinki, Finland
| | - Xuan Ling
- International Laboratory for Air Quality and Health, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, Queensland 4001, Australia
| | - Leigh Crilley
- International Laboratory for Air Quality and Health, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, Queensland 4001, Australia
| | - Nadeesha Jayasundara
- International Laboratory for Air Quality and Health, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, Queensland 4001, Australia
| | - Hing Cho Cheung
- International Laboratory for Air Quality and Health, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, Queensland 4001, Australia
| | - Megan Hargreaves
- International Laboratory for Air Quality and Health, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, Queensland 4001, Australia
| | - Flavia Huygens
- International Laboratory for Air Quality and Health, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, Queensland 4001, Australia
| | - Luke D Knibbs
- International Laboratory for Air Quality and Health, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, Queensland 4001, Australia; School of Population Health, The University of Queensland, Herston, Queensland 4006, Australia
| | - Godwin A Ayoko
- International Laboratory for Air Quality and Health, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, Queensland 4001, Australia
| | - Lidia Morawska
- International Laboratory for Air Quality and Health, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, Queensland 4001, Australia.
| |
Collapse
|
126
|
Madsen AM, Zervas A, Tendal K, Matthiesen CB, Koponen IK, Hansen EW. Exposure and preventive measure to reduce high and daily exposure to Bacillus thuringiensis in potted plant production. ACTA ACUST UNITED AC 2014; 58:664-76. [PMID: 24863937 DOI: 10.1093/annhyg/meu030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The bacterium Bacillus thuringiensis (Bt) is the active organism in a variety of commercially available products used worldwide as biopesticides. Bt products are applied in large outdoor areas as well as in indoor environments. Even though it has been sold for decades, not much is known about the occupational exposure to Bt. The aim of this study was to obtain knowledge about the exposure to Bt subspecies israelensis (Bti) in a propagation section in a greenhouse, where Bti is applied hourly by a spray boom, and to test a preventive measure to reduce the exposure to airborne Bti. Furthermore, we wanted to study the exposure during work with potted plants treated earlier with Bti. Exposure to aerosols with Bti was measured repeatedly by personal and stationary samplers before and after the intervention. Bti was identified by polymerase chain reaction in air and soil samples. Personal exposure to inhalable Bti in the propagation section was 3×10(5) cfu m(-3) (median level, n = 22); the personal exposure of people working with plants treated earlier with Bti was 3200 cfu m(-3) (median level, n = 17). The highest single measure was found for the person working with the spray boom (7×10(5) cfu m(-3)) but airborne Bti was present at all sampling stations in the propagation section. Bti constituted a high share of the airborne cultivable bacteria and a smaller share of the soilborne bacteria in the propagation section. In a human cell assay, spiking an aerosol sample with a product with Bti increased the inflammatory potential of an aerosol sample from the greenhouse significantly. Based on the inflammatory potential and the high personal exposure, a cover around the spray boom was built as an attempt to reduce the daily exposure to Bti. The cover reduced the personal exposure to Bti from 3.0×10(5) cfu m(-3) to 1.8×10(4) cfu m(-3). The exposure was thus reduced by a factor 17, which is a considerable reduction. Bti was present in different particle size fractions with the majority, both before and after the intervention, in the fraction of airborne particles with an aerodynamic diameter between 1.2 and 3.0 µm. The measured occupational exposure to Bti is discussed in relation to risk evaluation.
Collapse
Affiliation(s)
- Anne Mette Madsen
- 1.National Research Centre for the Working Environment, Lerso Parkalle 105, 2100 Copenhagen, Denmark
| | - Athanasios Zervas
- 1.National Research Centre for the Working Environment, Lerso Parkalle 105, 2100 Copenhagen, Denmark
| | - Kira Tendal
- 1.National Research Centre for the Working Environment, Lerso Parkalle 105, 2100 Copenhagen, Denmark
| | - Christoffer B Matthiesen
- 1.National Research Centre for the Working Environment, Lerso Parkalle 105, 2100 Copenhagen, Denmark
| | - Ismo Kalevi Koponen
- 1.National Research Centre for the Working Environment, Lerso Parkalle 105, 2100 Copenhagen, Denmark
| | - Erik Wind Hansen
- 2.Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 160, 2100 Copenhagen, Denmark
| |
Collapse
|
127
|
Data-driven discovery of seasonally linked diseases from an Electronic Health Records system. BMC Bioinformatics 2014; 15 Suppl 6:S3. [PMID: 25078762 PMCID: PMC4158606 DOI: 10.1186/1471-2105-15-s6-s3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Patterns of disease incidence can identify new risk factors for the disease or provide insight into the etiology. For example, allergies and infectious diseases have been shown to follow periodic temporal patterns due to seasonal changes in environmental or infectious agents. Previous work searching for seasonal or other temporal patterns in disease diagnosis rates has been limited both in the scope of the diseases examined and in the ability to distinguish unexpected seasonal patterns. Electronic Health Records (EHR) compile extensive longitudinal clinical information, constituting a unique source for discovery of trends in occurrence of disease. However, the data suffer from inherent biases that preclude an identification of temporal trends. METHODS Motivated by observation of the biases in this data source, we developed a method (Lomb-Scargle periodograms in detrended data, LSP-detrend) to find periodic patterns by adjusting the temporal information for broad trends in incidence, as well as seasonal changes in total hospitalizations. LSP-detrend can sensitively uncover periodic temporal patterns in the corrected data and identify the significance of the trend. We apply LSP-detrend to a compilation of records from 1.5 million patients encoded by ICD-9-CM (International Classification of Diseases, Ninth Revision, Clinical Modification), including 2,805 disorders with more than 500 occurrences across a 12 year period, recorded from 1.5 million patients. RESULTS AND CONCLUSIONS Although EHR data, and ICD-9 coded records in particular, were not created with the intention of aggregated use for research, these data can in fact be mined for periodic patterns in incidence of disease, if confounders are properly removed. Of all diagnoses, around 10% are identified as seasonal by LSP-detrend, including many known phenomena. We robustly reproduce previous findings, even for relatively rare diseases. For instance, Kawasaki disease, a rare childhood disease that has been associated with weather patterns, is detected as strongly linked with winter months. Among the novel results, we find a bi-annual increase in exacerbations of myasthenia gravis, a potentially life threatening complication of an autoimmune disease. We dissect the causes of this seasonal incidence and propose that factors predisposing patients to this event vary through the year.
Collapse
|
128
|
Frankel M, Hansen EW, Madsen AM. Effect of relative humidity on the aerosolization and total inflammatory potential of fungal particles from dust-inoculated gypsum boards. INDOOR AIR 2014; 24:16-28. [PMID: 23750665 DOI: 10.1111/ina.12055] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 06/04/2013] [Indexed: 06/02/2023]
Abstract
The aim of this study was to investigate the effect of relative humidity (RH) on the aerosolization and total inflammatory potential (TIP) of microbial particles released from gypsum boards inoculated with dust samples from homes. After microbial colonization, the gypsum boards were incubated at either high or low RH. The aerosolized particles (0.54-19.8 μm), culturable fungi, β-glucan and the TIP of the aerosolized particles were quantified. Despite the colonization of several fungal groups, Penicillium dominated the aerosolized fraction. Higher emission rates of particles and culturable fungi were found from low RH compared with high RH in both the inhalable and particulate matter <1 μm (PM1 ) fractions, and the TIP was accordingly higher. However, for the aerosolized fractions, the TIP or concentration β-glucan relative to the number of fungi or particles present was higher from high RH compared with low RH. Despite the low number of culturable fungi in PM1 , this fraction showed a high TIP, and the concentration of β-glucan correlated strongly with the TIP of this fraction. The individual particles of the aerosolized PM1 fraction were more inflammatory than the larger particles of the inhalable fraction, and β-glucan may be an important contributor to the inflammatory potential of the aerosolized particles.
Collapse
Affiliation(s)
- M Frankel
- The National Research Centre for the Working Environment, Copenhagen, Denmark; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | | |
Collapse
|
129
|
Kembel SW, Meadow JF, O’Connor TK, Mhuireach G, Northcutt D, Kline J, Moriyama M, Brown GZ, Bohannan BJM, Green JL. Architectural design drives the biogeography of indoor bacterial communities. PLoS One 2014; 9:e87093. [PMID: 24489843 PMCID: PMC3906134 DOI: 10.1371/journal.pone.0087093] [Citation(s) in RCA: 140] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 12/18/2013] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Architectural design has the potential to influence the microbiology of the built environment, with implications for human health and well-being, but the impact of design on the microbial biogeography of buildings remains poorly understood. In this study we combined microbiological data with information on the function, form, and organization of spaces from a classroom and office building to understand how design choices influence the biogeography of the built environment microbiome. RESULTS Sequencing of the bacterial 16S gene from dust samples revealed that indoor bacterial communities were extremely diverse, containing more than 32,750 OTUs (operational taxonomic units, 97% sequence similarity cutoff), but most communities were dominated by Proteobacteria, Firmicutes, and Deinococci. Architectural design characteristics related to space type, building arrangement, human use and movement, and ventilation source had a large influence on the structure of bacterial communities. Restrooms contained bacterial communities that were highly distinct from all other rooms, and spaces with high human occupant diversity and a high degree of connectedness to other spaces via ventilation or human movement contained a distinct set of bacterial taxa when compared to spaces with low occupant diversity and low connectedness. Within offices, the source of ventilation air had the greatest effect on bacterial community structure. CONCLUSIONS Our study indicates that humans have a guiding impact on the microbial biodiversity in buildings, both indirectly through the effects of architectural design on microbial community structure, and more directly through the effects of human occupancy and use patterns on the microbes found in different spaces and space types. The impact of design decisions in structuring the indoor microbiome offers the possibility to use ecological knowledge to shape our buildings in a way that will select for an indoor microbiome that promotes our health and well-being.
Collapse
Affiliation(s)
- Steven W. Kembel
- Département des sciences biologiques, Université du Québec à Montréal, Montréal, Québec, Canada
- Biology and the Built Environment Center, University of Oregon, Eugene, Oregon, United States of America
- Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon, United States of America
| | - James F. Meadow
- Biology and the Built Environment Center, University of Oregon, Eugene, Oregon, United States of America
- Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon, United States of America
- * E-mail:
| | - Timothy K. O’Connor
- Biology and the Built Environment Center, University of Oregon, Eugene, Oregon, United States of America
- Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon, United States of America
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona, United States of America
| | - Gwynne Mhuireach
- Biology and the Built Environment Center, University of Oregon, Eugene, Oregon, United States of America
- Energy Studies in Buildings Laboratory, University of Oregon, Eugene, Oregon, United States of America
| | - Dale Northcutt
- Biology and the Built Environment Center, University of Oregon, Eugene, Oregon, United States of America
- Energy Studies in Buildings Laboratory, University of Oregon, Eugene, Oregon, United States of America
| | - Jeff Kline
- Biology and the Built Environment Center, University of Oregon, Eugene, Oregon, United States of America
- Energy Studies in Buildings Laboratory, University of Oregon, Eugene, Oregon, United States of America
| | - Maxwell Moriyama
- Biology and the Built Environment Center, University of Oregon, Eugene, Oregon, United States of America
- Energy Studies in Buildings Laboratory, University of Oregon, Eugene, Oregon, United States of America
| | - G. Z. Brown
- Biology and the Built Environment Center, University of Oregon, Eugene, Oregon, United States of America
- Energy Studies in Buildings Laboratory, University of Oregon, Eugene, Oregon, United States of America
- Department of Architecture, University of Oregon, Eugene, Oregon, United States of America
| | - Brendan J. M. Bohannan
- Biology and the Built Environment Center, University of Oregon, Eugene, Oregon, United States of America
- Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon, United States of America
| | - Jessica L. Green
- Biology and the Built Environment Center, University of Oregon, Eugene, Oregon, United States of America
- Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon, United States of America
- Santa Fe Institute, Santa Fe, New Mexico, United States of America
| |
Collapse
|
130
|
Madsen AM, Tendal K, Frederiksen MW. Attempts to reduce exposure to fungi, β-glucan, bacteria, endotoxin and dust in vegetable greenhouses and a packaging unit. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 468-469:1112-21. [PMID: 24112965 DOI: 10.1016/j.scitotenv.2013.09.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 09/04/2013] [Accepted: 09/04/2013] [Indexed: 05/04/2023]
Abstract
Indoor handling of large amounts of plant materials occurs in different occupational settings including greenhouses and causes exposure to bioaerosols. The bioaerosol components fungi, β-glucan, bacteria and endotoxin are involved in different airway symptoms and health effects can be dose-dependent. Therefore, there is a persistent need to reduce exposure. The aims of this study were to identify tasks causing exposure and to evaluate preventive measures aimed at reducing exposure of greenhouse workers to bioaerosols, and to study factors affecting the exposure. We have focused on different exposure scenarios; one with high short-term exposure found during clearing of old cucumber plants; the other with long-term, mid-level exposure found during tomato picking, leaf nipping, stringing up tomato plants, and packaging of cucumbers. Clearing of non-dried cucumber plants compared with clearing of dried cucumber plants significantly reduced the exposure to dust, endotoxin, bacteria, fungal spores and β-glucan. More endotoxin and fungi are emitted and more of the emitted particles were of respirable size if the leaves were dried. Along the cucumber packaging line, exposure levels were highly specific to each personal subtask. The subtask 'unloading of cucumbers' was the source of exposure making task ventilation or shielding of the process a possibility. Elimination of leaf debris on the floor reduced the exposure to fungi significantly. However, leaf debris on the floor did not contribute significantly to the exposure to dust, endotoxin and bacteria. Furthermore, to eliminate leaf debris, it had to be cleared away and this was associated with a higher exposure to dust and endotoxin. The age of the plants affected the exposure level to bioaerosols with higher exposures from old plants. In conclusion, different tasks and subtasks cause very different exposure levels. It is possible to reduce exposure by identifying subtasks causing the exposure and by modifying work processes, e.g., not drying out of plants.
Collapse
Affiliation(s)
- Anne Mette Madsen
- The National Research Centre for the Working Environment, Lersø Parkallé 105, DK-2100 Copenhagen Ø, Denmark.
| | | | | |
Collapse
|
131
|
Madsen AM, Matthiesen CB, Frederiksen MW, Frederiksen M, Frankel M, Spilak M, Gunnarsen L, Timm M. Sampling, extraction and measurement of bacteria, endotoxin, fungi and inflammatory potential of settling indoor dust. ACTA ACUST UNITED AC 2012; 14:3230-9. [PMID: 23152160 DOI: 10.1039/c2em30699a] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Selection of sampling device, sampling location and period are important first steps in the measurement of exposure to bioaerosols in indoor air. The steps following the sampling include treatment of samples and laboratory analysis. In this study, settling bacteria, endotoxin, fungi and serine protease have been measured in Danish homes using Electrostatic Dust Fall Collectors (EDCs). The effects of the presence of occupants, sampling on open surfaces versus in bookcases and treatment of samples have been studied. Concentrations of bacteria and endotoxin were significantly higher when occupants were at home than when they were absent. Across homes, higher concentrations of fungi were found in spring than in winter, as was the total inflammatory potential, while higher concentrations of protease were found in winter than in spring. The placement of the EDCs in bookcases versus on an open surface significantly affected the measured concentrations of bacteria and endotoxin. Direct extraction of EDC cloths caused a higher measured concentration of bacteria, fungi and serine protease than if EDC cloths were extracted post-storage at -20 °C. Extraction of EDC cloths caused an average of 51% and 58% extraction of bacteria and fungi respectively. In conclusion, EDCs should be placed on open surfaces during the sampling, how much occupants are present in their home during sampling and sampling season should be considered, EDC cloths should not be stored in a freezer before extraction of microorganisms, but extraction suspensions can be stored at -80 °C without affecting the number of microorganisms significantly.
Collapse
Affiliation(s)
- Anne Mette Madsen
- The National Research Centre for the Working Environment, Lersø Parkallé 105, DK-2100 Copenhagen Ø, Denmark.
| | | | | | | | | | | | | | | |
Collapse
|