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Kvasnicka J, Cohen Hubal EA, Diamond ML. Modeling clothing as a secondary source of exposure to SVOCs across indoor microenvironments. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2024; 34:376-385. [PMID: 38129669 PMCID: PMC11144090 DOI: 10.1038/s41370-023-00621-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 11/27/2023] [Accepted: 11/28/2023] [Indexed: 12/23/2023]
Abstract
BACKGROUND Evidence suggests that clothing can influence human exposure to semi-volatile organic compounds (SVOCs) through transdermal uptake and inhalation. OBJECTIVES The objectives of this study were [1] to investigate the potential for clothing to function as a transport vector and secondary source of gas-phase SVOCs across indoor microenvironments, [2] to elucidate how clothing storage, wear, and laundering can influence the dynamics of transdermal uptake, and [3] to assess the potential for multiple human occupants to influence the multimedia dynamics of SVOCs indoors. METHODS A computational modeling framework (ABICAM) was expanded, applied, and evaluated by simulating and augmenting two "real-world" chamber experiments. A primary strength of this framework was its representation of occupants and their clothing as unique entities with the potential for location changes. RESULTS Estimates of transdermal uptake of diethyl phthalate (DEP) and di(n-butyl) phthalate (DnBP) were generally consistent with those extrapolated from measured concentrations of urinary metabolites, and those predicted by two other mechanistic models. ABICAM predicted that clean clothing (long sleeves, long pants, and socks, 100% cotton, 1 mm thick) readily accumulated DEP (6900-9700 μg) and DnBP (4500-4800 μg) from the surrounding chamber air over 6 h of exposure to average concentrations of 233 (DEP) and 114 (DnBP) μg·m-3. Because of their high capacity, clean clothing also effectively minimized transdermal uptake. In addition, ABICAM predicted that contaminated clothing functioned as a vector for transporting DEP and DnBP across indoor microenvironments and reemitted 13-80% (DEP) and 3-27% (DnBP) of the accumulated masses over 48 h. SIGNIFICANCE Though the estimated secondary inhalation exposures from contaminated clothing were low compared to the corresponding primary exposures, these secondary exposures could be accentuated in other contexts, for example, involving longer timeframes of clothing storage, multiple occupants wearing contaminated clothing, and/or repeated instances of clothing-mediated transport of contaminants (e.g., from an occupational setting). IMPACT This modeling study reaffirms the effectiveness of clean clothing in reducing transdermal uptake of airborne SVOCs and conversely, that contaminated clothing could be a source of SVOC exposure via transdermal uptake and by acting as a vector for transporting those contaminants to other locations.
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Affiliation(s)
- Jacob Kvasnicka
- Department of Earth Sciences, University of Toronto, Toronto, Ontario, M5S 3B1, Canada
| | - Elaine A Cohen Hubal
- Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Durham, NC, 27711, USA
| | - Miriam L Diamond
- Department of Earth Sciences, University of Toronto, Toronto, Ontario, M5S 3B1, Canada.
- School of the Environment, University of Toronto, Toronto, Ontario, M5S 3E8, Canada.
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Ijaz MK, Sattar SA, Nims RW, Boone SA, McKinney J, Gerba CP. Environmental dissemination of respiratory viruses: dynamic interdependencies of respiratory droplets, aerosols, aerial particulates, environmental surfaces, and contribution of viral re-aerosolization. PeerJ 2023; 11:e16420. [PMID: 38025703 PMCID: PMC10680453 DOI: 10.7717/peerj.16420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 10/17/2023] [Indexed: 12/01/2023] Open
Abstract
During the recent pandemic of COVID-19 (SARS-CoV-2), influential public health agencies such as the World Health Organization (WHO) and the U.S. Centers for Disease Control and Prevention (CDC) have favored the view that SARS CoV-2 spreads predominantly via droplets. Many experts in aerobiology have openly opposed that stance, forcing a vigorous debate on the topic. In this review, we discuss the various proposed modes of viral transmission, stressing the interdependencies between droplet, aerosol, and fomite spread. Relative humidity and temperature prevailing determine the rates at which respiratory aerosols and droplets emitted from an expiratory event (sneezing, coughing, etc.) evaporate to form smaller droplets or aerosols, or experience hygroscopic growth. Gravitational settling of droplets may result in contamination of environmental surfaces (fomites). Depending upon human, animal and mechanical activities in the occupied space indoors, viruses deposited on environmental surfaces may be re-aerosolized (re-suspended) to contribute to aerosols, and can be conveyed on aerial particulate matter such as dust and allergens. The transmission of respiratory viruses may then best be viewed as resulting from dynamic virus spread from infected individuals to susceptible individuals by various physical states of active respiratory emissions, instead of the current paradigm that emphasizes separate dissemination by respiratory droplets, aerosols or by contaminated fomites. To achieve the optimum outcome in terms of risk mitigation and infection prevention and control (IPAC) during seasonal infection peaks, outbreaks, and pandemics, this holistic view emphasizes the importance of dealing with all interdependent transmission modalities, rather than focusing on one modality.
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Affiliation(s)
- M. Khalid Ijaz
- Global Research & Development for Lysol and Dettol, Reckitt Benckiser LLC, Montvale, NJ, United States of America
| | - Syed A. Sattar
- Department of Biochemistry, Microbiology & Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | | | - Stephanie A. Boone
- Water & Energy Sustainable Technology Center, University of Arizona, Tucson, AZ, United States of America
| | - Julie McKinney
- Global Research & Development for Lysol and Dettol, Reckitt Benckiser LLC, Montvale, NJ, United States of America
| | - Charles P. Gerba
- Water & Energy Sustainable Technology Center, University of Arizona, Tucson, AZ, United States of America
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Anspaugh LR, Mauro J, Briggs N, Porrovecchio J, Amann W, Salame-Alfie A, Ansari A. A Methodology for Calculating Inhalation Dose to Public Health Personnel Exposed to Material Resuspended from Evacuees Following the Detonation of a Fission Device. HEALTH PHYSICS 2023; 125:289-304. [PMID: 37548561 PMCID: PMC10476581 DOI: 10.1097/hp.0000000000001720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/18/2023] [Indexed: 08/08/2023]
Abstract
ABSTRACT Following a nuclear fission event, there likely would be a large number of contaminated persons who would seek assistance at community reception centers to be established outside the affected area. This paper provides a methodology for calculating inhalation doses to public health and other response personnel at such facilities who would be receiving and assisting potentially contaminated persons from whom particles can be resuspended. Three hypothetical facilities were considered: the Base Case is a rather small room with no forced air ventilation. The Preferred Case, which is more realistic, is a mid-sized room with an operating HVAC system with air being recirculated through a filter. The Gymnasium Case has only fresh air intake. Initial bounding calculations for the Base Case indicated the need for pre-screening of arrivals to avoid unacceptable doses to staff. The screening criterion selected was 1.67 × 10 6 Bq m -2 . Calculations are presented for radionuclide concentrations in air, dose to staff from inhalation, and how exposures and the resulting doses can be altered by air-turnover rates and the use of filters with varying efficiency. Doses are presented for various arrival times and for both plutonium- and uranium-fueled detonations. The highest calculated dose via inhalation with no respiratory protection was 0.23 mSv for the Base Case. The more important radionuclides contributing to dose with exposure starting at day D + 1 were 239 Np and 133 I. At day D + 30, 131 I and 140 Ba were the more important dosimetrically. The variable creating the highest uncertainty was the slough-off factor for resuspension of contamination from people arriving at the reception center.
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Affiliation(s)
- Lynn R. Anspaugh
- Department of Radiology, University of Utah, Emeritus, Henderson, NV
- Associate, SC&A, Inc., Arlington, VA
| | | | | | - Joseph Porrovecchio
- Associate, SC&A, Inc., Arlington, VA
- Lt. Col., U.S. Army, Retired, Valley Cottage, NY
- Rockland County Sheriff’s Department, New City, NY
| | | | - Adela Salame-Alfie
- Radiation Studies Section, Division of Environmental Health Science and Practice, Centers for Disease Control and Prevention, Atlanta, GA
| | - Armin Ansari
- Radiation Studies Section, Division of Environmental Health Science and Practice, Centers for Disease Control and Prevention, Atlanta, GA
- Currently at Radiation Protection Division, Environmental Protection Agency, Washington, DC
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Moschovis PP, Lombay J, Rooney J, Schenkel SR, Singh D, Rezaei SJ, Salo N, Gong A, Yonker LM, Shah J, Hayden D, Hibberd PL, Demokritou P, Kinane TB. The effect of activity and face masks on exhaled particles in children. Pediatr Investig 2023; 7:75-85. [PMID: 37324601 PMCID: PMC10262878 DOI: 10.1002/ped4.12376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 01/29/2023] [Indexed: 06/17/2023] Open
Abstract
Importance Despite the high burden of respiratory infections among children, the production of exhaled particles during common activities and the efficacy of face masks in children have not been sufficiently studied. Objective To determine the effect of type of activity and mask usage on exhaled particle production in children. Methods Healthy children were asked to perform activities that ranged in intensity (breathing quietly, speaking, singing, coughing, and sneezing) while wearing no mask, a cloth mask, or a surgical mask. The concentration and size of exhaled particles were assessed during each activity. Results Twenty-three children were enrolled in the study. Average exhaled particle concentration increased by intensity of activity, with the lowest particle concentration during tidal breathing (1.285 particles/cm3 [95% CI 0.943, 1.627]) and highest particle concentration during sneezing (5.183 particles/cm3 [95% CI 1.911, 8.455]). High-intensity activities were associated with an increase primarily in the respirable size (≤ 5 µm) particle fraction. Surgical and cloth masks were associated with lower average particle concentration compared to no mask (P = 0.026 for sneezing). Surgical masks outperformed cloth masks across all activities, especially within the respirable size fraction. In a multivariable linear regression model, we observed significant effect modification of activity by age and by mask type. Interpretation Similar to adults, children produce exhaled particles that vary in size and concentration across a range of activities. Production of respirable size fraction particles (≤ 5 µm), the dominant mode of transmission of many respiratory viruses, increases significantly with coughing and sneezing and is most effectively reduced by wearing surgical face masks.
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Affiliation(s)
- Peter P. Moschovis
- Department of PediatricsMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA
| | - Jesiel Lombay
- Department of PediatricsMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA
| | - Jennifer Rooney
- Department of PediatricsMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA
| | - Sara R. Schenkel
- Department of PediatricsMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA
| | - Dilpreet Singh
- Department of Environmental HealthHarvard T. H. Chan School of Public HealthBostonMassachusettsUSA
- Department of Mechanical and Aerospace EngineeringRutgers University School of Public HealthNew BrunswickNew JerseyUSA
| | - Shawheen J. Rezaei
- Department of PediatricsMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA
| | - Nora Salo
- Department of PediatricsMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA
| | - Amanda Gong
- David Geffen School of Medicinethe University of California Los AngelesLos AngelesCaliforniaUSA
| | - Lael M. Yonker
- Department of PediatricsMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA
| | - Jhill Shah
- Department of PediatricsMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA
| | - Douglas Hayden
- Department of PediatricsMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA
| | - Patricia L. Hibberd
- Department of Global HealthBoston University School of Public HealthBostonMassachusettsUSA
| | - Philip Demokritou
- Department of Environmental HealthHarvard T. H. Chan School of Public HealthBostonMassachusettsUSA
- Department of Mechanical and Aerospace EngineeringRutgers University School of Public HealthNew BrunswickNew JerseyUSA
| | - T. Bernard Kinane
- Department of PediatricsMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA
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Yang S, Muthalagu A, Serrano VG, Licina D. Human personal air pollution clouds in a naturally ventilated office during the COVID-19 pandemic. BUILDING AND ENVIRONMENT 2023; 236:110280. [PMID: 37064616 PMCID: PMC10080864 DOI: 10.1016/j.buildenv.2023.110280] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 03/31/2023] [Accepted: 04/05/2023] [Indexed: 05/03/2023]
Abstract
Personal cloud, termed as the difference in air pollutant concentrations between breathing zone and room sites, represents the bias in approximating personal inhalation exposure that is linked to accuracy of health risk assessment. This study performed a two-week field experiment in a naturally ventilated office during the COVID-19 pandemic to assess occupants' exposure to common air pollutants and to determine factors contributing to the personal cloud effect. During occupied periods, indoor average concentrations of endotoxin (0.09 EU/m3), TVOC (231 μg/m3), CO2 (630 ppm), and PM10 (14 μg/m3) were below the recommended limits, except for formaldehyde (58 μg/m3). Personal exposure concentrations, however, were significantly different from, and mostly higher than, concentrations measured at room stationary sampling sites. Although three participants shared the same office, their personal air pollution clouds were mutually distinct. The mean personal cloud magnitude ranged within 0-0.05 EU/m3, 35-192 μg/m3, 32-120 ppm, and 4-9 μg/m3 for endotoxin, TVOC, CO2, and PM10, respectively, and was independent from room concentrations. The use of hand sanitizer was strongly associated with an elevated personal cloud of endotoxin and alcohol-based VOCs. Reduced occupancy density in the office resulted in more pronounced personal CO2 clouds. The representativeness of room stationary sampling for capturing dynamic personal exposures was as low as 28% and 5% for CO2 and PM10, respectively. The findings of our study highlight the necessity of considering the personal cloud effect when assessing personal exposure in offices.
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Affiliation(s)
- Shen Yang
- Human-Oriented Built Environment Lab, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Akila Muthalagu
- Human-Oriented Built Environment Lab, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Environmental Systems Group, Department of Civil Engineering, Indian Institute of Technology Hyderabad, Kandi, India
| | - Viviana González Serrano
- Human-Oriented Built Environment Lab, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Dusan Licina
- Human-Oriented Built Environment Lab, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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Rumchev K, Van Hoang D, Lee AH. Exposure to dust and respiratory health among Australian miners. Int Arch Occup Environ Health 2023; 96:355-363. [PMID: 36089622 PMCID: PMC9968258 DOI: 10.1007/s00420-022-01922-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 09/01/2022] [Indexed: 02/03/2023]
Abstract
PURPOSE Occupational exposure to dust has been recognised as a significant health hazard to mine workers. This study aimed to investigate the association between exposure to inhalable (INH) and respirable (RES) dust and respiratory health among mine workers in Western Australia using an industry-wide exposure database. METHODS The database comprised cross-sectional surveys conducted by mining companies for the period 2001-2012. The study population consisted of 12,797 workers who were monitored for exposure to INH and RES dust and undertook health assessments including a respiratory questionnaire and spirometry test. RESULTS Despite the general trend of declining exposure to both INH and RES dust observed over the 12 years period, mine workers reported a higher prevalence of phlegm and cough when exposed to elevated concentrations of INH and RES dust. Logistic regression analysis further confirmed the positive association between INH dust exposure and the prevalence of phlegm with an adjusted odds ratio of 1.033 (95% CI 1.012-1.052). Overall, 6.3% of miners might have potential airway obstruction, and exposure to INH dust was associated with impaired lung function parameters. CONCLUSION Exposure levels of INH and RES dust particles among mine workers have reduced considerably and were well below currently legislated occupational exposure limits. However, given the reported higher prevalence of phlegm and cough among those with elevated dust concentrations, there is a continued need for effective dust exposure monitoring and control in the mineral mining industry.
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Affiliation(s)
- Krassi Rumchev
- School of Public Health, Curtin University, Perth, Australia.
| | - Dong Van Hoang
- National Center for Global Health and Medicine, Tokyo, Japan
| | - Andy H. Lee
- School of Public Health, Curtin University, Perth, Australia
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Rohra H, Pipal AS, Satsangi PG, Taneja A. Revisiting the atmospheric particles: Connecting lines and changing paradigms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 841:156676. [PMID: 35700785 DOI: 10.1016/j.scitotenv.2022.156676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 06/09/2022] [Accepted: 06/09/2022] [Indexed: 06/15/2023]
Abstract
Historically, the atmospheric particles constitute the most primitive and recent class of air pollutants. The science of atmospheric particles erupted more than a century ago covering more than four decades of size, with past few years experiencing major advancements on both theoretic and data-based observational grounds. More recently, the plausible recognition between particulate matter (PM) and the diffusion of the COVID-19 pandemic has led to the accretion of interest in particle science. With motivation from diverse particle research interests, this paper is an 'old engineer's survey' beginning with the evolution of atmospheric particles and identifies along the way many of the global instances signaling the 'size concept' of PM. A theme that runs through the narrative is a 'previously known' generational evolution of particle science to the 'newly procured' portfolio of knowledge, with important gains on the application of unmet concepts and future approaches to PM exposure and epidemiological research.
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Affiliation(s)
- Himanshi Rohra
- Department of Chemistry, Savitribai Phule Pune University, Pune 411007, India
| | - Atar Singh Pipal
- Centre for Environmental Sustainability and Human Health, Ming Chi University of Technology, Taishan, New Taipei 243089, Taiwan
| | - P G Satsangi
- Department of Chemistry, Savitribai Phule Pune University, Pune 411007, India
| | - Ajay Taneja
- Department of Chemistry, Dr. Bhimrao Ambedkar University, Agra 282002, India.
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Kvasnicka J, Cohen Hubal EA, Siegel JA, Scott JA, Diamond ML. Modeling Clothing as a Vector for Transporting Airborne Particles and Pathogens across Indoor Microenvironments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:5641-5652. [PMID: 35404579 PMCID: PMC9069698 DOI: 10.1021/acs.est.1c08342] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 03/19/2022] [Accepted: 03/21/2022] [Indexed: 06/14/2023]
Abstract
Evidence suggests that human exposure to airborne particles and associated contaminants, including respiratory pathogens, can persist beyond a single microenvironment. By accumulating such contaminants from air, clothing may function as a transport vector and source of "secondary exposure". To investigate this function, a novel microenvironmental exposure modeling framework (ABICAM) was developed. This framework was applied to a para-occupational exposure scenario involving the deposition of viable SARS-CoV-2 in respiratory particles (0.5-20 μm) from a primary source onto clothing in a nonhealthcare setting and subsequent resuspension and secondary exposure in a car and home. Variability was assessed through Monte Carlo simulations. The total volume of infectious particles on the occupant's clothing immediately after work was 4800 μm3 (5th-95th percentiles: 870-32 000 μm3). This value was 61% (5-95%: 17-300%) of the occupant's primary inhalation exposure in the workplace while unmasked. By arrival at the occupant's home after a car commute, relatively rapid viral inactivation on cotton clothing had reduced the infectious volume on clothing by 80% (5-95%: 26-99%). Secondary inhalation exposure (after work) was low in the absence of close proximity and physical contact with contaminated clothing. In comparison, the average primary inhalation exposure in the workplace was higher by about 2-3 orders of magnitude. It remains theoretically possible that resuspension and physical contact with contaminated clothing can occasionally transmit SARS-CoV-2 between humans.
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Affiliation(s)
- Jacob Kvasnicka
- Department
of Earth Sciences, University of Toronto, Toronto, Ontario M5S 3B1, Canada
| | - Elaine A. Cohen Hubal
- Center
for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Durham, North Carolina 27711, United States
| | - Jeffrey A. Siegel
- Department
of Civil and Mineral Engineering, University
of Toronto, Toronto, Ontario M5S 1A4, Canada
- Dalla
Lana School of Public Health, University
of Toronto, Toronto, Ontario M5T 3M7, Canada
| | - James A. Scott
- Dalla
Lana School of Public Health, University
of Toronto, Toronto, Ontario M5T 3M7, Canada
- Department
of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, University of Toronto, 1 King’s College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Miriam L. Diamond
- Department
of Earth Sciences, University of Toronto, Toronto, Ontario M5S 3B1, Canada
- Dalla
Lana School of Public Health, University
of Toronto, Toronto, Ontario M5T 3M7, Canada
- School of
the Environment, University of Toronto, Toronto, Ontario M5S 3E8, Canada
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Peimbert M, Alcaraz LD. Where environmental microbiome meets its host: subway and passenger microbiome relationships. Mol Ecol 2022; 32:2602-2618. [PMID: 35318755 DOI: 10.1111/mec.16440] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 03/12/2022] [Accepted: 03/16/2022] [Indexed: 12/17/2022]
Abstract
Subways are urban transport systems with high capacity. Every day around the world, there are more than 150 million subway passengers. Since 2013, thousands of microbiome samples from various subways worldwide have been sequenced. Skin bacteria and environmental organisms dominate the subway microbiomes. The literature has revealed common bacterial groups in subway systems; even so, it is possible to identify cities by their microbiome. Low-frequency bacteria are responsible for specific bacterial fingerprints of each subway system. Furthermore, daily subway commuters leave their microbial clouds and interact with other passengers. Microbial exchange is quite fast; the hand microbiome changes within minutes, and after cleaning the handrails, the bacteria are re-established within minutes. To investigate new taxa and metabolic pathways of subway microbial communities, several high-quality metagenomic-assembled genomes (MAG) have been described. Subways are harsh environments unfavorable for microorganism growth. However, recent studies have observed a wide diversity of viable and metabolically active bacteria. Understanding which bacteria are living, dormant, or dead allows us to propose realistic ecological interactions. Questions regarding the relationship between humans and the subway microbiome, particularly the microbiome effects on personal and public health, remain unanswered. This review summarizes our knowledge of subway microbiomes and their relationship with passenger microbiomes.
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Affiliation(s)
- Mariana Peimbert
- Departamento de Ciencias Naturales, Unidad Cuajimalpa, Universidad Autónoma Metropolitana. Ciudad de México, México
| | - Luis D Alcaraz
- Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad de México, México
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Cheng P, Luo K, Xiao S, Yang H, Hang J, Ou C, Cowling BJ, Yen HL, Hui DS, Hu S, Li Y. Predominant airborne transmission and insignificant fomite transmission of SARS-CoV-2 in a two-bus COVID-19 outbreak originating from the same pre-symptomatic index case. JOURNAL OF HAZARDOUS MATERIALS 2022; 425:128051. [PMID: 34910996 PMCID: PMC8656245 DOI: 10.1016/j.jhazmat.2021.128051] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 12/06/2021] [Accepted: 12/07/2021] [Indexed: 05/22/2023]
Abstract
The number of people infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to increase worldwide, but despite extensive research, there remains significant uncertainty about the predominant routes of SARS-CoV-2 transmission. We conducted a mechanistic modeling and calculated the exposure dose and infection risk of each passenger in a two-bus COVID-19 outbreak in Hunan province, China. This outbreak originated from a single pre-symptomatic index case. Some human behavioral data related to exposure including boarding and alighting time of some passengers and seating position and mask wearing of all passengers were obtained from the available closed-circuit television images/clips and/or questionnaire survey. Least-squares fitting was performed to explore the effect of effective viral load on transmission risk, and the most likely quanta generation rate was also estimated. This study reveals the leading role of airborne SARS-CoV-2 transmission and negligible role of fomite transmission in a poorly ventilated indoor environment, highlighting the need for more targeted interventions in such environments. The quanta generation rate of the index case differed by a factor of 1.8 on the two buses and transmission occurred in the afternoon of the same day, indicating a time-varying effective viral load within a short period of five hours.
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Affiliation(s)
- Pan Cheng
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
| | - Kaiwei Luo
- Hunan Provincial Center for Disease Control and Prevention, Changsha, China
| | - Shenglan Xiao
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China; School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Hongyu Yang
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
| | - Jian Hang
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
| | - Cuiyun Ou
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
| | | | - Hui-Ling Yen
- School of Public Health, The University of Hong Kong, Hong Kong, China
| | - David Sc Hui
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China
| | - Shixiong Hu
- Hunan Provincial Center for Disease Control and Prevention, Changsha, China
| | - Yuguo Li
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China; School of Public Health, The University of Hong Kong, Hong Kong, China.
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11
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Møller SA, Rasmussen PU, Frederiksen MW, Madsen AM. Work clothes as a vector for microorganisms: Accumulation, transport, and resuspension of microorganisms as demonstrated for waste collection workers. ENVIRONMENT INTERNATIONAL 2022; 161:107112. [PMID: 35091375 DOI: 10.1016/j.envint.2022.107112] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 01/18/2022] [Accepted: 01/21/2022] [Indexed: 05/04/2023]
Abstract
Work clothes may act as a vector for the transport of microorganisms leading to second-hand exposure; however, this has not been studied in work environments. We investigated whether microorganisms accumulate on workers' clothes in environments with elevated microbial exposures, and whether they are transported with the clothes and subsequently resuspended to the air. To study this, we selected waste collection workers and potential transport of bacteria and fungi to waste truck cabs via clothes, and compared the microbial communities within truck cabs, in waste collection workers' personal exposure, and on clean T-shirts worn by the workers. Microbial communities were also investigated for the presence of potentially harmful microorganisms. Results showed that microorganisms accumulated in large quantities (GM = 3.69 × 105 CFU/m2/h for bacteria, GM = 8.29 × 104 CFU/m2/h for fungi) on workers' clothes. The concentrations and species composition of airborne fungi in the truck cabs correlated significantly with the accumulation and composition of fungi on clothes and correlated to concentrations (a trend) and species composition of their personal exposures. The same patterns were not found for bacteria, indicating that work clothes to a lesser degree act as a vector for bacteria under waste collection workers' working conditions compared to fungi. Several pathogenic or allergenic microorganisms were present, e.g.: Klebsiella oxytoca, K. pneumoniae, Proteus mirabilis, Providencia rettgeri, Pseudomonas aeruginosa, and Aspergillus fumigatus, A. glaucus, A. nidulans, A. niger, and various Penicillium species. The potential 'take-home' exposure to these microorganisms are of most concern for immunocompromised or atopic individuals or people with open wounds or cuts. In conclusion, the large accumulation of microorganisms on workers' clothes combined with the overlap between fungal species for the different sample types, and the presence of pathogenic and allergenic microorganisms forms the basis for encouragement of good clothing hygiene during and post working hours.
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Affiliation(s)
- Signe Agnete Møller
- The National Research Centre for the Working Environment, Lersø Parkallé 105, DK-2100 Copenhagen Ø, Denmark
| | - Pil Uthaug Rasmussen
- The National Research Centre for the Working Environment, Lersø Parkallé 105, DK-2100 Copenhagen Ø, Denmark
| | - Margit W Frederiksen
- The National Research Centre for the Working Environment, Lersø Parkallé 105, DK-2100 Copenhagen Ø, Denmark
| | - Anne Mette Madsen
- The National Research Centre for the Working Environment, Lersø Parkallé 105, DK-2100 Copenhagen Ø, Denmark.
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12
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Salthammer T, Fauck C, Omelan A, Wientzek S, Uhde E. Time and spatially resolved tracking of the air quality in local public transport. Sci Rep 2022; 12:3262. [PMID: 35228615 PMCID: PMC8885640 DOI: 10.1038/s41598-022-07290-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 02/16/2022] [Indexed: 12/28/2022] Open
Abstract
As an indoor environment, public transport is subject to special conditions with many passengers in a comparatively small space. Therefore, both an efficient control of the climatic parameters and a good air exchange are necessary to avoid transmission and spread of respiratory diseases. However, in such a dynamic system it is practically impossible to determine pathogenic substances with the necessary temporal and spatial resolution, but easy-to-measure parameters allow the air quality to be assessed in a passenger compartment. Carbon dioxide has already proven to be a useful indicator, especially in environments with a high occupancy of people. Airborne particulate matter can also be an important aspect for assessing the air quality in an indoor space. Consequently, the time courses of temperature, relative humidity, carbon dioxide and particulate matter (PM10) were tracked and evaluated in local public transport buses, trams and trains in the Brunswick/Hanover region. In all measurements, the climatic conditions were comfortable for the passengers. Carbon dioxide was strongly correlated with occupancy and has proven to be the most informative parameter. The PM10 concentration, however, often correlated with the dynamics of people when getting on and off, but not with the occupancy. Sensors, equipped with integrated GPS, were installed in the passenger cabins and were found to be useful for recording location-related effects such as stops. The results of this study show that the online recording of simple parameters is a valuable tool for assessing air quality as a function of time, location and number of people. When the occupancy is high, a low carbon dioxide level indicates good ventilation, which automatically reduces the risk of infection. It is therefore recommended to take more advantage of low-cost sensors as a control for air conditioning systems in passenger cabins and for evaluations of the dynamics in public transport.
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Affiliation(s)
- Tunga Salthammer
- Department of Material Analysis and Indoor Chemistry, Fraunhofer WKI, Bienroder Weg 54 E, 38108, Brunswick, Germany.
| | - Christian Fauck
- Department of Material Analysis and Indoor Chemistry, Fraunhofer WKI, Bienroder Weg 54 E, 38108, Brunswick, Germany
| | - Alexander Omelan
- Department of Material Analysis and Indoor Chemistry, Fraunhofer WKI, Bienroder Weg 54 E, 38108, Brunswick, Germany
| | - Sebastian Wientzek
- Department of Material Analysis and Indoor Chemistry, Fraunhofer WKI, Bienroder Weg 54 E, 38108, Brunswick, Germany
| | - Erik Uhde
- Department of Material Analysis and Indoor Chemistry, Fraunhofer WKI, Bienroder Weg 54 E, 38108, Brunswick, Germany
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13
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Ren J, Tang M, Novoselac A. Experimental study to quantify airborne particle deposition onto and resuspension from clothing using a fluorescent-tracking method. BUILDING AND ENVIRONMENT 2022; 209:108580. [PMID: 34848915 PMCID: PMC8620412 DOI: 10.1016/j.buildenv.2021.108580] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 10/10/2021] [Accepted: 11/10/2021] [Indexed: 05/22/2023]
Abstract
The rapid spread and high level of morbidity of the SARS-CoV-2 virus during the COVID-19 pandemic has attracted considerable attention worldwide. Recent studies have shown that clothing is one of the vectors for the transport of airborne particles, including bioaerosols. This study developed a method that can both quantify the deposition of particles onto clothing and the resuspension of particles from clothing using a fluorescent-tracking technology and found that electrical tape can be used as a fluorescent particle collector on irregular clothing surfaces. Results show that 0.07%-6.61% of the fluorescent particles (FPs) previously loaded on the room flooring surfaces moved to the occupant's clothing during the 20-min sampling periods; the percentage depended on the type of activity and the range is for: office work, walking, and vacuuming. Furthermore, both the flooring type (carpet or vinyl composition tile) and flooring condition (clean or dirty) had significant effects on particle resuspension and transport to the occupant's clothing. The average particle deposition factor for carpet flooring was 2.7 (±1.4) times that for vinyl composition tile flooring, while the average particle deposition factor for dirty flooring was 2.4 (±1.6) times that for clean flooring. A multiple regression analysis shows that the activity type had the largest effect on the particle transport among all experimental variables. An additional experiment performed in a full-scale house shows that 46.8% of FPs formerly seeded on clothing resuspended from clothing and dispersed around the house during the 1-h period of light walking at a speed of 60 steps/min.
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Affiliation(s)
- Jianlin Ren
- School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, China
| | - Mengjia Tang
- Department of Civil, Architectural, and Environmental Engineering, University of Texas at Austin, USA
| | - Atila Novoselac
- Department of Civil, Architectural, and Environmental Engineering, University of Texas at Austin, USA
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14
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Xu J, Wang C, Fu SC, Chao CYH. The effect of head orientation and personalized ventilation on bioaerosol deposition from a cough. INDOOR AIR 2022; 32:e12973. [PMID: 34888956 DOI: 10.1111/ina.12973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 11/29/2021] [Accepted: 12/01/2021] [Indexed: 06/13/2023]
Abstract
Head orientations directly determine movement directions of exhaled pathogen-laden droplets, while there is a lack of research about the effect of the infected person's head orientations on respiratory disease transmission during close contact. This work experimentally investigated the effect of different head orientations of an infected person (IP) on the bioaerosol deposition on a healthy person (HP) during close contact. Also, the effectiveness of PV flow in reducing bioaerosol deposition on the HP under the IP's different head orientations was investigated. Bacteriophage T3 was employed to represent viruses inside the cough-generated aerosols. The bioaerosol depositions on different locations of the HP's upper body (chest, shoulder, and neck) and face (chin, mucous membranes, cheek, and forehead) were characterized by a cultivation method. Results showed that the IP's different head orientations resulted in significantly different deposition density on the HP. PV flow could reduce the bioaerosol deposition remarkably for most cases investigated. The effectiveness of PV flow in reducing deposition on the HP was significantly affected by the IP's head orientations. Findings suggest that changing head orientations can be a control measure to reduce the bioaerosol deposition. Personalized ventilation can be a potential method to reduce the bioaerosol deposition on the HP.
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Affiliation(s)
- Jingcui Xu
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - Cunteng Wang
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
| | - Sau Chung Fu
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
| | - Christopher Y H Chao
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
- Department of Building Environment and Energy Engineering, Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hong Kong, China
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15
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Nazaroff WW. Indoor aerosol science aspects of SARS-CoV-2 transmission. INDOOR AIR 2022; 32:e12970. [PMID: 34873752 DOI: 10.1111/ina.12970] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 11/17/2021] [Accepted: 11/26/2021] [Indexed: 05/04/2023]
Abstract
Knowledge about person-to-person transmission of SARS-CoV-2 is reviewed, emphasizing three components: emission of virus-containing particles and drops from infectious persons; transport and fate of such emissions indoors; and inhalation of viral particles by susceptible persons. Emissions are usefully clustered into three groups: small particles (diameter 0.1-5 µm), large particles (5-100 µm), and ballistic drops (>100 µm). Speaking generates particles and drops across the size spectrum. Small particles are removed from indoor air at room scale by ventilation, filtration, and deposition; large particles mainly deposit onto indoor surfaces. Proximate exposure enhancements are associated with large particles with contributions from ballistic drops. Masking and social distancing are effective in mitigating transmission from proximate exposures. At room scale, masking, ventilation, and filtration can contribute to limit exposures. Important information gaps prevent a quantitative reconciliation of the high overall global spread of COVID-19 with known transmission pathways. Available information supports several findings with moderate-to-high confidence: transmission occurs predominantly indoors; inhalation of airborne particles (up to 50 µm in diameter) contributes substantially to viral spread; transmission occurs in near proximity and at room scale; speaking is a major source of airborne SARS-CoV-2 virus; and emissions can occur without strong illness symptoms.
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Affiliation(s)
- William W Nazaroff
- Department of Civil and Environmental Engineering, University of California, Berkeley, California, USA
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16
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Al Assaad D, Yang S, Licina D. Particle release and transport from human skin and clothing: A CFD modeling methodology. INDOOR AIR 2021; 31:1377-1390. [PMID: 33896029 DOI: 10.1111/ina.12840] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 04/04/2021] [Accepted: 04/08/2021] [Indexed: 05/04/2023]
Abstract
Particle release from human skin and clothing has been identified as an important contributor to particulate matter burden indoors. However, knowledge about modeling the coarse particle release from skin and clothing is limited. This study developed a new empirically validated CFD modeling methodology for particle release and transport from seated occupants in an office setting. We tested three modeling approaches for particle emissions: Uniform; Uniform + Localized; and Uniform + Localized with Body Motion; applied to four office scenarios involving a single occupant and two occupants facing each other at 1- and 2-m distances. Uniform particle emissions from skin and clothing underpredicted personal inhalation exposure by as much as 55%-80%. Combining uniform with localized emissions from the armpits drastically reduced the error margin to <10%. However, this modeling approach heavily underestimated particle mass exchange (cross-contamination) between the occupants. Accounting for the occupant's body motion-by applying the momentum theory method-yielded the most accurate personal exposure and cross-contamination results, with errors below 12%. The study suggests that for accurate modeling of particle release and transport from seated occupants indoors, localized body emissions in combination with simplified bodily movements need to be taken into account.
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Affiliation(s)
- Douaa Al Assaad
- Mechanical Engineering Department, American University of Beirut, Beirut, Lebanon
| | - Shen Yang
- Human-Oriented Built Environment Lab, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Dusan Licina
- Human-Oriented Built Environment Lab, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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17
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Feld-Cook E, Shome R, Zaleski RT, Mohan K, Kourtev H, Bekris KE, Weisel CP, Shin JMK. Exploring the utility of robots in exposure studies. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2021; 31:784-794. [PMID: 31745180 PMCID: PMC7234925 DOI: 10.1038/s41370-019-0190-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 08/30/2019] [Accepted: 09/10/2019] [Indexed: 06/10/2023]
Abstract
Obtaining valid, reliable quantitative exposure data can be a significant challenge for industrial hygienists, exposure scientists, and other health science professionals. In this proof-of-concept study, a robotic platform was programmed to perform a simple task as a plausible alternative to human subjects in exposure studies for generating exposure data. The use of robots offers several advantages over the use of humans. Research can be completed more efficiently and there is no need to recruit, screen, or train volunteers. In addition, robots can perform tasks repeatedly without getting tired allowing for collection of an unlimited number of measurements using different chemicals to assess exposure impacts from formulation changes and new product development. The use of robots also eliminates concerns with intentional human exposures while removing health research ethics review requirements which are time consuming. In this study, a humanoid robot was programmed to paint drywall, while volatile organic compounds were measured in air for comparison to model estimates. The measured air concentrations generally agreed with more advanced exposure model estimates. These findings suggest that robots have potential as a methodology for generating exposure measurements relevant to human activities, but without using human subjects.
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Affiliation(s)
- Elisabeth Feld-Cook
- Environmental and Occupational Health Sciences Institute, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Rahul Shome
- PRACSYS Lab, Department of Computer Science, School of Arts and Sciences at Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | | | - Krishnan Mohan
- Environmental and Occupational Health Sciences Institute, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Hristiyan Kourtev
- PRACSYS Lab, Department of Computer Science, School of Arts and Sciences at Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Kostas E Bekris
- PRACSYS Lab, Department of Computer Science, School of Arts and Sciences at Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Clifford P Weisel
- Environmental and Occupational Health Sciences Institute, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
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18
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Relationship between Indoor High Frequency Size Distribution of Ultrafine Particles and Their Metrics in a University Site. SUSTAINABILITY 2021. [DOI: 10.3390/su13105504] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Exposure to ultrafine particles (UFPs size < 100 nm) in life and work environments can contribute to adverse health effects also in terms of health burden of related diseases over time. The choice of parameters which better characterize UFPs is challenging, due to their physical-chemical properties and their variable size. It is also strictly related to the availability of different instrumental techniques. In the present study we focus on real time high frequency (1 Hz) UFPs particle size distribution (PSD) and their relationship with total particle number concentration (TPNC) and mean particle diameter (Davg) as a contribution characterizing by size the human exposure to UFPs in an indoor site of the University of Rome “Sapienza” (Italy). Further considerations about UFPs contribution to nucleation mode (NM) and accumulation mode (AM) have been highlighted, also in order to investigate the contribution of polycyclic aromatic hydrocarbons (PAHs) surface-adsorbed on indoor air particles (pPAHs). High indoor TPNC values were registered during the rush hours (early morning and mid/late afternoon) according to the outdoor influences originated from anthropogenic activities. AM mainly contribute to the indoor TPNC during working days showing high correlation with pPAHs. These findings may provide useful indications in terms of occupational exposure to UFPs since there are many evidences that indoor exposures to such pollutants may be associated with adverse health effects also in working environments.
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19
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Yang S, Bekö G, Wargocki P, Williams J, Licina D. Human Emissions of Size-Resolved Fluorescent Aerosol Particles: Influence of Personal and Environmental Factors. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:509-518. [PMID: 33337850 DOI: 10.1021/acs.est.0c06304] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Human emissions of fluorescent aerosol particles (FAPs) can influence the biological burden of indoor air. Yet, quantification of FAP emissions from human beings remains limited, along with a poor understanding of the underlying emission mechanisms. To reduce the knowledge gap, we characterized human emissions of size-segregated FAPs (1-10 μm) and total particles in a climate chamber with low-background particle levels. We probed the influence of several personal factors (clothing coverage and age) and environmental parameters (level of ozone, air temperature, and relative humidity) on particle emissions from human volunteers. A material-balance model showed that the mean emission rate ranged 5.3-16 × 106 fluorescent particles per person-h (0.30-1.2 mg per person-h), with a dominant size mode within 3-5 μm. Volunteers wearing long-sleeve shirts and pants produced 40% more FAPs relative to those wearing t-shirts and shorts. Particle emissions varied across the age groups: seniors (average age 70.5 years) generated 50% fewer FAPs compared to young adults (25.0 years) and teenagers (13.8 years). While we did not observe a measurable influence of ozone (0 vs 40 ppb) on human FAP emissions, there was a strong influence of relative humidity (34 vs 62%), with FAP emissions decreasing by 30-60% at higher humidity.
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Affiliation(s)
- Shen Yang
- Human-Oriented Built Environment Lab, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Gabriel Bekö
- International Centre for Indoor Environment and Energy, Department of Civil Engineering, Technical University of Denmark, 2800 Lyngby, Denmark
| | - Pawel Wargocki
- International Centre for Indoor Environment and Energy, Department of Civil Engineering, Technical University of Denmark, 2800 Lyngby, Denmark
| | - Jonathan Williams
- Max Planck Institute for Chemistry, Hahn-Meitner Weg 1, 55128 Mainz, Germany
- Energy, Environment and Water Research Center, The Cyprus Institute, 2121 Nicosia, Cyprus
| | - Dusan Licina
- Human-Oriented Built Environment Lab, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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20
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Grydaki N, Colbeck I, Mendes L, Eleftheriadis K, Whitby C. Bioaerosols in the Athens Metro: Metagenetic insights into the PM 10 microbiome in a naturally ventilated subway station. ENVIRONMENT INTERNATIONAL 2021; 146:106186. [PMID: 33126062 DOI: 10.1016/j.envint.2020.106186] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 07/30/2020] [Accepted: 10/02/2020] [Indexed: 06/11/2023]
Abstract
To date, few studies have examined the aerosol microbial content in Metro transportation systems. Here we characterised the aerosol microbial abundance, diversity and composition in the Athens underground railway system. PM10 filter samples were collected from the naturally ventilated Athens Metro Line 3 station "Nomismatokopio". Quantitative PCR of the 16S rRNA gene and high throughput amplicon sequencing of the 16S rRNA gene and internal transcribed spacer (ITS) region was performed on DNA extracted from PM10 samples. Results showed that, despite the bacterial abundance (mean = 2.82 × 105 16S rRNA genes/m3 of air) being, on average, higher during day-time and weekdays, compared to night-time and weekends, respectively, the differences were not statistically significant. The average PM10 mass concentration on the platform was 107 μg/m3. However, there was no significant correlation between 16S rRNA gene abundance and overall PM10 levels. The Athens Metro air microbiome was mostly dominated by bacterial and fungal taxa of environmental origin (e.g. Paracoccus, Sphingomonas, Cladosporium, Mycosphaerella, Antrodia) with a lower contribution of human commensal bacteria (e.g. Corynebacterium, Staphylococcus). This study highlights the importance of both outdoor air and commuters as sources in shaping aerosol microbial communities. To our knowledge, this is the first study to characterise the mycobiome diversity in the air of a Metro environment based on amplicon sequencing of the ITS region. In conclusion, this study presents the first microbial characterisation of PM10 in the Athens Metro, contributing to the growing body of microbiome exploration within urban transit networks. Moreover, this study shows the vulnerability of public transport to airborne disease transmission.
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Affiliation(s)
- N Grydaki
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ Essex, UK
| | - I Colbeck
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ Essex, UK
| | - L Mendes
- Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety - Environmental Radioactivity Laboratory, N.C.S.R. "Demokritos", Aghia Paraskevi, 15310 Athens, Greece
| | - K Eleftheriadis
- Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety - Environmental Radioactivity Laboratory, N.C.S.R. "Demokritos", Aghia Paraskevi, 15310 Athens, Greece
| | - C Whitby
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ Essex, UK.
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21
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Asadi S, Cappa CD, Barreda S, Wexler AS, Bouvier NM, Ristenpart WD. Efficacy of masks and face coverings in controlling outward aerosol particle emission from expiratory activities. Sci Rep 2020. [PMID: 32973285 DOI: 10.1038/s414598-020-72798-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023] Open
Abstract
The COVID-19 pandemic triggered a surge in demand for facemasks to protect against disease transmission. In response to shortages, many public health authorities have recommended homemade masks as acceptable alternatives to surgical masks and N95 respirators. Although mask wearing is intended, in part, to protect others from exhaled, virus-containing particles, few studies have examined particle emission by mask-wearers into the surrounding air. Here, we measured outward emissions of micron-scale aerosol particles by healthy humans performing various expiratory activities while wearing different types of medical-grade or homemade masks. Both surgical masks and unvented KN95 respirators, even without fit-testing, reduce the outward particle emission rates by 90% and 74% on average during speaking and coughing, respectively, compared to wearing no mask, corroborating their effectiveness at reducing outward emission. These masks similarly decreased the outward particle emission of a coughing superemitter, who for unclear reasons emitted up to two orders of magnitude more expiratory particles via coughing than average. In contrast, shedding of non-expiratory micron-scale particulates from friable cellulosic fibers in homemade cotton-fabric masks confounded explicit determination of their efficacy at reducing expiratory particle emission. Audio analysis of the speech and coughing intensity confirmed that people speak more loudly, but do not cough more loudly, when wearing a mask. Further work is needed to establish the efficacy of cloth masks at blocking expiratory particles for speech and coughing at varied intensity and to assess whether virus-contaminated fabrics can generate aerosolized fomites, but the results strongly corroborate the efficacy of medical-grade masks and highlight the importance of regular washing of homemade masks.
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Affiliation(s)
- Sima Asadi
- Department of Chemical Engineering, University of California Davis, 1 Shields Ave, Davis, CA, 95616, USA
| | - Christopher D Cappa
- Department of Civil and Environmental Engineering, University of California Davis, 1 Shields Ave, Davis, CA, 95616, USA
| | - Santiago Barreda
- Department of Linguistics, University of California Davis, 1 Shields Ave, Davis, CA, 95616, USA
| | - Anthony S Wexler
- Department of Civil and Environmental Engineering, University of California Davis, 1 Shields Ave, Davis, CA, 95616, USA
- Department of Mechanical and Aerospace Engineering, University of California Davis, 1 Shields Ave, Davis, CA, 95616, USA
- Air Quality Research Center, University of California Davis, 1 Shields Ave, Davis, CA, 95616, USA
- Department of Land, Air and Water Resources, University of California Davis, 1 Shields Ave, Davis, CA, 95616, USA
| | - Nicole M Bouvier
- Department of Medicine, Division of Infectious Diseases, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY, 10029, USA
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY, 10029, USA
| | - William D Ristenpart
- Department of Chemical Engineering, University of California Davis, 1 Shields Ave, Davis, CA, 95616, USA.
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22
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Asadi S, Cappa CD, Barreda S, Wexler AS, Bouvier NM, Ristenpart WD. Efficacy of masks and face coverings in controlling outward aerosol particle emission from expiratory activities. Sci Rep 2020; 10:15665. [PMID: 32973285 PMCID: PMC7518250 DOI: 10.1038/s41598-020-72798-7] [Citation(s) in RCA: 187] [Impact Index Per Article: 46.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 08/23/2020] [Indexed: 12/20/2022] Open
Abstract
The COVID-19 pandemic triggered a surge in demand for facemasks to protect against disease transmission. In response to shortages, many public health authorities have recommended homemade masks as acceptable alternatives to surgical masks and N95 respirators. Although mask wearing is intended, in part, to protect others from exhaled, virus-containing particles, few studies have examined particle emission by mask-wearers into the surrounding air. Here, we measured outward emissions of micron-scale aerosol particles by healthy humans performing various expiratory activities while wearing different types of medical-grade or homemade masks. Both surgical masks and unvented KN95 respirators, even without fit-testing, reduce the outward particle emission rates by 90% and 74% on average during speaking and coughing, respectively, compared to wearing no mask, corroborating their effectiveness at reducing outward emission. These masks similarly decreased the outward particle emission of a coughing superemitter, who for unclear reasons emitted up to two orders of magnitude more expiratory particles via coughing than average. In contrast, shedding of non-expiratory micron-scale particulates from friable cellulosic fibers in homemade cotton-fabric masks confounded explicit determination of their efficacy at reducing expiratory particle emission. Audio analysis of the speech and coughing intensity confirmed that people speak more loudly, but do not cough more loudly, when wearing a mask. Further work is needed to establish the efficacy of cloth masks at blocking expiratory particles for speech and coughing at varied intensity and to assess whether virus-contaminated fabrics can generate aerosolized fomites, but the results strongly corroborate the efficacy of medical-grade masks and highlight the importance of regular washing of homemade masks.
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Affiliation(s)
- Sima Asadi
- Department of Chemical Engineering, University of California Davis, 1 Shields Ave, Davis, CA, 95616, USA
| | - Christopher D Cappa
- Department of Civil and Environmental Engineering, University of California Davis, 1 Shields Ave, Davis, CA, 95616, USA
| | - Santiago Barreda
- Department of Linguistics, University of California Davis, 1 Shields Ave, Davis, CA, 95616, USA
| | - Anthony S Wexler
- Department of Civil and Environmental Engineering, University of California Davis, 1 Shields Ave, Davis, CA, 95616, USA.,Department of Mechanical and Aerospace Engineering, University of California Davis, 1 Shields Ave, Davis, CA, 95616, USA.,Air Quality Research Center, University of California Davis, 1 Shields Ave, Davis, CA, 95616, USA.,Department of Land, Air and Water Resources, University of California Davis, 1 Shields Ave, Davis, CA, 95616, USA
| | - Nicole M Bouvier
- Department of Medicine, Division of Infectious Diseases, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY, 10029, USA.,Department of Microbiology, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY, 10029, USA
| | - William D Ristenpart
- Department of Chemical Engineering, University of California Davis, 1 Shields Ave, Davis, CA, 95616, USA.
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23
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Choi YJ, Park J, Seong S, Oh JW. Effects of Mechanical Drying on the Removal of Pollen Allergens. Int Arch Allergy Immunol 2020; 181:675-679. [PMID: 32615568 DOI: 10.1159/000508694] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 05/15/2020] [Indexed: 11/19/2022] Open
Abstract
PURPOSE Pollen may spread indoors through clothes contaminated during outdoor activities. This study aimed to evaluate the pollen removal efficacy of a mechanical dryer. METHODS Cotton clothes served as laundry, and fabrics measuring 2 × 5 cm served as test samples. Pollen was spread evenly on the test fabrics. The fabrics were then fixed on the cloth and left for 8 h to imitate real-life conditions. This experiment was conducted under 2 conditions, wet (after washing clothes) and dry (without washing). After drying, we counted pollen on the test fabrics to evaluate the pollen removal rate. We measured the remaining allergens in extracts from the contaminated fabrics after mechanical drying. The concentrations of allergens (Amb a 1, Bet v 1, Crp j 1, and Phl p 1) in each extracted solution were measured using 2-site ELISA. RESULTS For ragweed, Japanese cedar, birch, and timothy grass, the mean pollen removal ratios for the dry samples were 99.88 ± 0.09%, 99.96 ± 0.03%, 99.89 ± 0.02%, and 99.82 ± 0.11%, respectively, and those for the wet samples were 98.83 ± 0.87%, 97.91 ± 1.81%, 97.29 ± 1.19%, and 96.3 ± 0.92%, respectively. Further, for the pollen allergens Amb a 1 [ragweed], Crp j 1 [Japanese cedar], Bet v 1 [birch], and Phl p 1 [timothy grass], the mean pollen allergen removal ratios for the dry samples were 99.81 ± 0.06%, 99.94 ± 0.23%, 99.90 ± 0.11%, and 99.84 ± 0.17%, respectively, and those for the wet samples were 98.11 ± 0.14%, 96.04 ± 1.52%, 97.21 ± 0.83%, and 95.23 ± 0.92%, respectively. There was no statistically significant difference for each species. CONCLUSIONS Mechanical drying effectively removed pollen and allergens from dry and wet fabrics. We expect that further studies on the removal of other indoor allergens would contribute to improved environmental control for allergy patients.
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Affiliation(s)
- Young-Jin Choi
- Department of Pediatrics, Hanyang University Guri Hospital, Guri, Republic of Korea
| | - Jungha Park
- Digital Appliances R&D Center, Samsung Electronics Co, Suwon, Republic of Korea
| | - Sujin Seong
- Advanced R&D Team, Digital Appliances, Samsung Electronics Co, Suwon, Republic of Korea
| | - Jae-Won Oh
- Department of Pediatrics, Hanyang University Guri Hospital, Guri, Republic of Korea,
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24
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Pantelic J, Liu S, Pistore L, Licina D, Vannucci M, Sadrizadeh S, Ghahramani A, Gilligan B, Sternberg E, Kampschroer K, Schiavon S. Personal CO 2 cloud: laboratory measurements of metabolic CO 2 inhalation zone concentration and dispersion in a typical office desk setting. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2020; 30:328-337. [PMID: 31636369 DOI: 10.1038/s41370-019-0179-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 07/30/2019] [Accepted: 08/23/2019] [Indexed: 06/10/2023]
Abstract
Inhalation exposure to pure and metabolic elevated carbon dioxide (CO2) concentration has been associated with impaired work performance, lower perceived air quality, and increased health symptoms. In this study, the concentration of metabolic CO2 was continuously measured in the inhalation zone of 41 subjects performing simulated office work. The measurements took place in an environmental chamber with well-controlled mechanical ventilation arranged as an office environment. The results showed the existence of a personal CO2 cloud in the inhalation zone of all test subjects, characterized by the excess of metabolic CO2 beyond the room background levels. For seated occupants, the median CO2 inhalation zone concentration levels were between 200 and 500 ppm above the background, and the third quartile up to 800 ppm above the background. Each study subject had distinct magnitude of the personal CO2 cloud owing to differences in metabolic CO2 generation, posture, nose geometry, and breathing pattern. A small desktop oscillating fan proved to be suitable for dispersing much of the personal CO2 cloud, thus reducing the inhalation zone concentration to background level. The results suggest that background measurements cannot capture the significant personal CO2 cloud effect in human microclimate.
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Affiliation(s)
- Jovan Pantelic
- Center for the Built Environment, University of California Berkeley, Berkeley, CA, USA.
| | - Shichao Liu
- Center for the Built Environment, University of California Berkeley, Berkeley, CA, USA
- Department of Civil and Environmental Engineering, Worcester Polytechnic Institute, 100 Institute Rd, WPI - Kaven Hall, Worcester, MA, 01609, USA
| | - Lorenza Pistore
- Center for the Built Environment, University of California Berkeley, Berkeley, CA, USA
- Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università, 5, 39100, Bolzano, BZ, Italy
| | - Dusan Licina
- Human-Oriented Built Environment Lab, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, CH-1015, Lausanne, Switzerland
| | - Matthew Vannucci
- Center for the Built Environment, University of California Berkeley, Berkeley, CA, USA
| | - Sasan Sadrizadeh
- Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA, 94720, USA
| | - Ali Ghahramani
- Center for the Built Environment, University of California Berkeley, Berkeley, CA, USA
| | - Brian Gilligan
- General Services Administration, 1800 F St NW, Washington, DC, 20405, USA
| | - Esther Sternberg
- Institute on Place, Wellbeing and Performance, University of Arizona College of Medicine, P.O. Box 245153, Tuscon, AZ, 85724, USA
| | - Kevin Kampschroer
- General Services Administration, 1800 F St NW, Washington, DC, 20405, USA
| | - Stefano Schiavon
- Center for the Built Environment, University of California Berkeley, Berkeley, CA, USA
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25
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Licina D, Morrison GC, Bekö G, Weschler CJ, Nazaroff WW. Clothing-Mediated Exposures to Chemicals and Particles. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:5559-5575. [PMID: 31034216 DOI: 10.1021/acs.est.9b00272] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A growing body of evidence identifies clothing as an important mediator of human exposure to chemicals and particles, which may have public health significance. This paper reviews and critically assesses the state of knowledge regarding how clothing, during wear, influences exposure to molecular chemicals, abiotic particles, and biotic particles, including microbes and allergens. The underlying processes that govern the acquisition, retention, and transmission of clothing-associated contaminants and the consequences of these for subsequent exposures are explored. Chemicals of concern have been identified in clothing, including byproducts of their manufacture and chemicals that adhere to clothing during use and care. Analogously, clothing acts as a reservoir for biotic and abiotic particles acquired from occupational and environmental sources. Evidence suggests that while clothing can be protective by acting as a physical or chemical barrier, clothing-mediated exposures can be substantial in certain circumstances and may have adverse health consequences. This complex process is influenced by the type and history of the clothing; the nature of the contaminant; and by wear, care, and storage practices. Future research efforts are warranted to better quantify, predict, and control clothing-related exposures.
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Affiliation(s)
- Dusan Licina
- Human-Oriented Built Environment Lab, School of Architecture, Civil and Environmental Engineering , École Polytechnique Fédérale de Lausanne , CH-1015 Lausanne , Switzerland
| | - Glenn C Morrison
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health , The University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States
| | - Gabriel Bekö
- International Centre for Indoor Environment and Energy, Department of Civil Engineering , Technical University of Denmark , Lyngby 2800 , Denmark
| | - Charles J Weschler
- International Centre for Indoor Environment and Energy, Department of Civil Engineering , Technical University of Denmark , Lyngby 2800 , Denmark
- Environmental and Occupational Health Sciences Institute , Rutgers University , Piscataway , New Jersey 08901 , United States
| | - William W Nazaroff
- Department of Civil and Environmental Engineering , University of California , Berkeley , California 94720-1710 , United States
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