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Ehelepola N, Thilakarathna HA. Respiratory infection transmission risk and indoor air quality at outpatient departments and emergency treatment units of Sri Lankan teaching hospitals. PLOS GLOBAL PUBLIC HEALTH 2024; 4:e0002862. [PMID: 38408038 PMCID: PMC10896534 DOI: 10.1371/journal.pgph.0002862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 01/04/2024] [Indexed: 02/28/2024]
Abstract
Indoor carbon dioxide (CO2) concentration has been used as a proxy of the degree of ventilation and, by extension, as an indicator of the risk of contracting respiratory infections. No publications exist regarding indoor air quality (IAQ) parameters of Sri Lankan hospitals.We measured the levels of CO2 and seven other IAQ parameters during morning rush hours for three days, in outpatient departments (OPDs) and emergency treatment units (ETUs) of all 21 teaching hospitals of Sri Lanka. We measured the same parameters of outdoor air also. We calculated the mean values of those parameters. We looked for correlations between outdoors and OPD and ETU levels of selected air quality parameters.The average CO2 levels of outdoors, OPDs and ETUs respectively were 514ppm (ppm = parts per million), 749ppm and 795ppm. The average levels of PM2.5 (particulate matter with diameters <2.5μm) outdoors, OPDs and ETUs respectively, were 28.7μg/m3,32μg/m3 and 25.6 μg/m3. The average levels of PM10 (particulate matter with diameters <10μm) outdoors, OPDs and ETUs respectively, were 49.4μg/m3, 55.5μg/m3 and 47.9 μg/m3. The median levels of formaldehyde outdoors, OPDs and ETUs respectively, were 0.03mg/m3, 0.04mg/m3 and 0.08mg/m3. The median levels of total volatile organic compounds (VOC) outdoors, OPDs and ETUs respectively were 0.12mg/m3, 0.19mg/m3 and 0.38mg/m3.CO2 levels of air in OPDs and ETUs generally were below the national ceilings but above the ceilings used by some developed countries. Outdoors, OPDs and ETUs air contain PM10, PM2.5 levels higher than WHO ceilings, although below the national ceilings. VOC and formaldehyde levels are generally below the national ceilings. Air in OPDs and ETUs is hotter and humid than national ceilings. Outdoor PM10, PM2.5 levels influence OPDs and ETUs levels. We propose methods to reduce the risk of nosocomial respiratory infections and to improve IAQ of Sri Lankan OPDs and ETUs.
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Alonso-Blanco E, Gómez-Moreno FJ, Díaz-Ramiro E, Fernández J, Coz E, Yagüe C, Román-Cascón C, Narros A, Borge R, Artíñano B. Real-Time Measurements of Indoor-Outdoor Exchange of Gaseous and Particulate Atmospheric Pollutants in an Urban Area. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:6823. [PMID: 37835093 PMCID: PMC10572255 DOI: 10.3390/ijerph20196823] [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: 07/04/2023] [Revised: 08/31/2023] [Accepted: 09/12/2023] [Indexed: 10/15/2023]
Abstract
Air pollution is one of the greatest environmental risks to health, causing millions of deaths and deleterious health effects worldwide, especially in urban areas where citizens are exposed to high ambient levels of pollutants, also influencing indoor air quality (IAQ). Many sources of indoor air are fairly obvious and well known, but the contribution of outside sources to indoor air still leads to significant uncertainties, in particular the influence that environmental variables have on outdoor/indoor pollutant exchange mechanisms. This is a critical aspect to consider in IAQ studies. In this respect, an experimental study was performed at a public site such as a university classroom during a non-academic period in Madrid city. This includes two field campaigns, in summer (2021) and winter (2020), where instruments for measuring gases and particle air pollutants simultaneously measured outdoor and indoor real-time concentrations. This study aimed to investigate the dynamic variations in the indoor/outdoor (I/O) ratios in terms of ambient outdoor conditions (meteorology, turbulence and air quality) and indoor features (human presence or natural ventilation). The results show that the I/O ratio is pollutant-dependent. In this sense, the infiltration capacity is higher for gaseous compounds, and in the case of particles, it depends on the particle size, with a higher infiltration capacity for smaller particles (
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Affiliation(s)
- Elisabeth Alonso-Blanco
- Department of Environment, CIEMAT (Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas), 28040 Madrid, Spain; (F.J.G.-M.); (E.D.-R.); (J.F.); (E.C.); (B.A.)
| | - Francisco Javier Gómez-Moreno
- Department of Environment, CIEMAT (Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas), 28040 Madrid, Spain; (F.J.G.-M.); (E.D.-R.); (J.F.); (E.C.); (B.A.)
| | - Elías Díaz-Ramiro
- Department of Environment, CIEMAT (Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas), 28040 Madrid, Spain; (F.J.G.-M.); (E.D.-R.); (J.F.); (E.C.); (B.A.)
| | - Javier Fernández
- Department of Environment, CIEMAT (Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas), 28040 Madrid, Spain; (F.J.G.-M.); (E.D.-R.); (J.F.); (E.C.); (B.A.)
| | - Esther Coz
- Department of Environment, CIEMAT (Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas), 28040 Madrid, Spain; (F.J.G.-M.); (E.D.-R.); (J.F.); (E.C.); (B.A.)
| | - Carlos Yagüe
- Department of Earth Physics and Astrophysics, Complutense University of Madrid, 28040 Madrid, Spain;
| | - Carlos Román-Cascón
- Department of Applied Physics, Marine and Environmental Sciences Faculty, INMAR, CEIMAR, University of Cadiz, 11519 Puerto Real, Cádiz, Spain;
| | - Adolfo Narros
- Department of Chemical and Environmental Engineering, Technical University of Madrid (UPM), 28006 Madrid, Spain; (A.N.); (R.B.)
| | - Rafael Borge
- Department of Chemical and Environmental Engineering, Technical University of Madrid (UPM), 28006 Madrid, Spain; (A.N.); (R.B.)
| | - Begoña Artíñano
- Department of Environment, CIEMAT (Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas), 28040 Madrid, Spain; (F.J.G.-M.); (E.D.-R.); (J.F.); (E.C.); (B.A.)
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Chou YA, Wang ZY, Chang HC, Liu YC, Su PF, Huang YT, Yang CT, Lai CH. Indoor CO 2 monitoring in a surgical intensive care unit under visitation restrictions during the COVID-19 pandemic. Front Med (Lausanne) 2023; 10:1052452. [PMID: 37521349 PMCID: PMC10375033 DOI: 10.3389/fmed.2023.1052452] [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: 09/24/2022] [Accepted: 06/30/2023] [Indexed: 08/01/2023] Open
Abstract
Background Indoor CO2 concentration is an important metric of indoor air quality (IAQ). The dynamic temporal pattern of CO2 levels in intensive care units (ICUs), where healthcare providers experience high cognitive load and occupant numbers are frequently changing, has not been comprehensively characterized. Objective We attempted to describe the dynamic change in CO2 levels in the ICU using an Internet of Things-based (IoT-based) monitoring system. Specifically, given that the COVID-19 pandemic makes hospital visitation restrictions necessary worldwide, this study aimed to appraise the impact of visitation restrictions on CO2 levels in the ICU. Methods Since February 2020, an IoT-based intelligent indoor environment monitoring system has been implemented in a 24-bed university hospital ICU, which is symmetrically divided into areas A and B. One sensor was placed at the workstation of each area for continuous monitoring. The data of CO2 and other pollutants (e.g., PM2.5) measured under standard and restricted visitation policies during the COVID-19 pandemic were retrieved for analysis. Additionally, the CO2 levels were compared between workdays and non-working days and between areas A and B. Results The median CO2 level (interquartile range [IQR]) was 616 (524-682) ppm, and only 979 (0.34%) data points obtained in area A during standard visitation were ≥ 1,000 ppm. The CO2 concentrations were significantly lower during restricted visitation (median [IQR]: 576 [556-596] ppm) than during standard visitation (628 [602-663] ppm; p < 0.001). The PM2.5 concentrations were significantly lower during restricted visitation (median [IQR]: 1 [0-1] μg/m3) than during standard visitation (2 [1-3] μg/m3; p < 0.001). The daily CO2 and PM2.5 levels were relatively low at night and elevated as the occupant number increased during clinical handover and visitation. The CO2 concentrations were significantly higher in area A (median [IQR]: 681 [653-712] ppm) than in area B (524 [504-547] ppm; p < 0.001). The CO2 concentrations were significantly lower on non-working days (median [IQR]: 606 [587-671] ppm) than on workdays (583 [573-600] ppm; p < 0.001). Conclusion Our study suggests that visitation restrictions during the COVID-19 pandemic may affect CO2 levels in the ICU. Implantation of the IoT-based IAQ sensing network system may facilitate the monitoring of indoor CO2 levels.
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Affiliation(s)
- Ying-An Chou
- Department of Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Zheng-Yao Wang
- Department of Computer Science, Tunghai University, Taichung, Taiwan
- UniSmart Technology Co., Ltd., Taichung, Taiwan
| | - Hsiang-Ching Chang
- Department of Computer Science, Tunghai University, Taichung, Taiwan
- UniSmart Technology Co., Ltd., Taichung, Taiwan
| | - Yi-Chia Liu
- Department of Statistics, College of Management, National Cheng Kung University, Tainan, Taiwan
| | - Pei-Fang Su
- Department of Statistics, College of Management, National Cheng Kung University, Tainan, Taiwan
| | - Yen Ta Huang
- Department of Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chao-Tung Yang
- Department of Computer Science, Tunghai University, Taichung, Taiwan
- Research Center for Smart Sustainable Circular Economy, Tunghai University, Taichung, Taiwan
| | - Chao-Han Lai
- Department of Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN, United States
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Sarwar G, Hogrefe C, Henderson BH, Foley K, Mathur R, Murphy B, Ahmed S. Characterizing variations in ambient PM 2.5 concentrations at the U.S. Embassy in Dhaka, Bangladesh using observations and the CMAQ modeling system. ATMOSPHERIC ENVIRONMENT (OXFORD, ENGLAND : 1994) 2023; 296:119587. [PMID: 37854171 PMCID: PMC10581604 DOI: 10.1016/j.atmosenv.2023.119587] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2023]
Abstract
We analyze hourly PM2.5 (particles with an aerodynamic diameter of ≤ 2.5 μm) concentrations measured at the U.S. Embassy in Dhaka over the 2016 - 2021 time period and find that concentrations are seasonally dependent with the highest occurring in winter and the lowest in monsoon seasons. Mean winter PM2.5 concentrations reached ~165-175 μg/m3 while monsoon concentrations remained ~30-35 μg/m3. Annual mean PM2.5 concentration reached ~5-6 times greater than the Bangladesh annual PM2.5 standard of 15 μg/m3. The number of days exceeding the daily PM2.5 standard of 65 μg/m3 in a year approached nearly 50%. Daily-mean PM2.5 concentrations remained elevated (>65 μg/m3) for more than 80 consecutive days. Night-time concentrations were greater than daytime concentrations. The comparison of results obtained from the Community Multiscale Air Quality (CMAQ) model simulations over the Northern Hemisphere using 108-km horizontal grids with observed data suggests that the model can reproduce the seasonal variation of observed data but underpredicts observed PM2.5 in winter months with a normalized mean bias of 13-32%. In the model, organic aerosol is the largest component of PM2.5, of which secondary organic aerosol plays a dominant role. Transboundary pollution has a large impact on the PM2.5 concentration in Dhaka, with an annual mean contribution of ~40 μg/m3.
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Affiliation(s)
- Golam Sarwar
- Center for Environmental Measurement & Modeling, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Christian Hogrefe
- Center for Environmental Measurement & Modeling, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Barron H. Henderson
- Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Kristen Foley
- Center for Environmental Measurement & Modeling, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Rohit Mathur
- Center for Environmental Measurement & Modeling, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Ben Murphy
- Center for Environmental Measurement & Modeling, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Shoeb Ahmed
- Department of Chemical Engineering, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladesh
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Akteruzzaman M, Rahman MA, Rabbi FM, Asharof S, Rofi MM, Hasan MK, Muktadir Islam MA, Khan MAR, Rahman MM, Rahaman MH. The impacts of cooking and indoor air quality assessment in the southwestern region of Bangladesh. Heliyon 2023; 9:e12852. [PMID: 36711262 PMCID: PMC9880388 DOI: 10.1016/j.heliyon.2023.e12852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 01/04/2023] [Accepted: 01/04/2023] [Indexed: 01/09/2023] Open
Abstract
The main objective of this study is to assess the impacts of cooking and indoor air quality (IAQ) in the southwestern region of Bangladesh. Here we report and compare the IAQ in considering a total of eight kitchens and living rooms of four selected households (HHs) in Jashore city and suburb area, the southwest district of Bangladesh. Air quality parameters, such as particulate matter (PM2.5) and volatile organic compounds (VOC), were assessed continuously for 24 h. In addition, Carbon dioxide (CO2) was evaluated in different phases during the study period. PM2.5, VOC, and CO2 levels were ranged from 18.52 to 207 μg/m3, 7.95-35.66 ppm, and 1061-2459 mg/m3, respectively, in the indoor cooking HHs. Conversely, while the average concentration was found between 20.63 and 23.72 μg/m3 PM2.5, 11.18-12.36 ppm VOC, and 1097-1747 mg/m3 CO2 in the outdoor cooking HHs. A significant increase in CO2 due to kitchen activities (cooking, frying, boiling) was observed that ranged between 5 and 77% compared to the background level. The calculated range of toxicity potential (TP) values was between 0.8 and 8.3 for PM2.5 in the HHs. In most of the observations, PM2.5, VOC, and CO2 exceed the standard values. The study reports that well ventilation systems and clean fuel use significantly reduce the indoor air contaminants level. Our study offers new insights about the IAQ of the southwest region of Bangladesh, particularly for suburbs and urban setups, and provides a background for further study, and decision-making. It will serve as a reference for the formulation and implementation of policies to improve air quality.
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Affiliation(s)
- Md. Akteruzzaman
- Department of Environmental Science and Technology, Jashore University of Science and Technology, Jashore 7408, Bangladesh
| | - Md. Alinur Rahman
- Department of Environmental Science and Technology, Jashore University of Science and Technology, Jashore 7408, Bangladesh
| | - Fahim Muntasir Rabbi
- Department of Environmental Science and Technology, Jashore University of Science and Technology, Jashore 7408, Bangladesh
| | - Sohely Asharof
- Department of Environmental Science and Technology, Jashore University of Science and Technology, Jashore 7408, Bangladesh
| | - Mahi Muzammel Rofi
- Department of Environmental Science and Technology, Jashore University of Science and Technology, Jashore 7408, Bangladesh
| | - Md. Kamrul Hasan
- Department of Environmental Science and Technology, Jashore University of Science and Technology, Jashore 7408, Bangladesh
| | - Md. Abdul Muktadir Islam
- Department of Chemistry, Jashore University of Science and Technology (JUST), Jashore 7408, Bangladesh
| | - M. Azizur R. Khan
- Department of Chemistry, Jashore University of Science and Technology (JUST), Jashore 7408, Bangladesh
| | - Mohammad Mahfuzur Rahman
- Department of Environmental Science and Technology, Jashore University of Science and Technology, Jashore 7408, Bangladesh
| | - Md. Hasibur Rahaman
- Department of Environmental Science and Technology, Jashore University of Science and Technology, Jashore 7408, Bangladesh,Corresponding author.
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Ali MA, Bilal M, Wang Y, Qiu Z, Nichol JE, Mhawish A, de Leeuw G, Zhang Y, Shahid S, Almazroui M, Islam MN, Rahman MA, Mondol SK, Tiwari P, Khedher KM. Spatiotemporal changes in aerosols over Bangladesh using 18 years of MODIS and reanalysis data. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 315:115097. [PMID: 35504182 DOI: 10.1016/j.jenvman.2022.115097] [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: 07/25/2021] [Revised: 04/13/2022] [Accepted: 04/16/2022] [Indexed: 06/14/2023]
Abstract
In this study, combined Dark Target and Deep Blue (DTB) aerosol optical depth at 550 nm (AOD550 nm) data the Moderate Resolution Imaging Spectroradiometer (MODIS) flying on the Terra and Aqua satellites during the years 2003-2020 are used as a reference to assess the performance of the Copernicus Atmosphere Monitoring Services (CAMS) and the second version of Modern-Era Retrospective analysis for Research and Applications (MERRA-2) AOD over Bangladesh. The study also investigates long-term spatiotemporal variations and trends in AOD, and determines the relative contributions from different aerosol species (black carbon: BC, dust, organic carbon: OC, sea salt: SS, and sulfate) and anthropogenic emissions to the total AOD. As the evaluations suggest higher accuracy for CAMS than for MERRA-2, CAMS is used for further analysis of AOD over Bangladesh. The annual mean AOD from both CAMS and MODIS DTB is high (>0.60) over most parts of Bangladesh except for the eastern areas of Chattogram and Sylhet. Higher AOD is observed in spring and winter than in summer and autumn, which is mainly due to higher local anthropogenic emissions during the winter to spring season. Annual trends from 2003-2020 show a significant increase in AOD (by 0.006-0.014 year-1) over Bangladesh, and this increase in AOD was more evident in winter and spring than in summer and autumn. The increasing total AOD is caused by rising anthropogenic emissions and accompanied by changes in aerosol species (with increased OC, sulfate, and BC). Overall, this study improves understanding of aerosol pollution in Bangladesh and can be considered as a supportive document for Bangladesh to improve air quality by reducing anthropogenic emissions.
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Affiliation(s)
- Md Arfan Ali
- Lab of Environmental Remote Sensing (LERS), School of Marine Sciences (SMS), Nanjing University of Information Science and Technology (NUIST), Nanjing, 210044, China
| | - Muhammad Bilal
- Lab of Environmental Remote Sensing (LERS), School of Marine Sciences (SMS), Nanjing University of Information Science and Technology (NUIST), Nanjing, 210044, China
| | - Yu Wang
- Lab of Environmental Remote Sensing (LERS), School of Marine Sciences (SMS), Nanjing University of Information Science and Technology (NUIST), Nanjing, 210044, China
| | - Zhongfeng Qiu
- Lab of Environmental Remote Sensing (LERS), School of Marine Sciences (SMS), Nanjing University of Information Science and Technology (NUIST), Nanjing, 210044, China.
| | - Janet E Nichol
- Department of Geography, School of Global Studies, University of Sussex, Brighton, BN19RH, UK
| | - Alaa Mhawish
- Lab of Environmental Remote Sensing (LERS), School of Marine Sciences (SMS), Nanjing University of Information Science and Technology (NUIST), Nanjing, 210044, China
| | - Gerrit de Leeuw
- Royal Netherlands Meteorological Institute (KNMI), R & D Satellite Observations, 3730AE De Bilt, the Netherlands; Aerospace Information Research Institute, Chinese Academy of Sciences (AirCAS), No.20 Datun Road, Chaoyang District, Beijing, 100101, China; School of Atmospheric Physics, Nanjing University of Information Science and Technology (NUIST), Nanjing, 210044, China; School of Environment Science and Spatial Informatics, University of Mining and Technology, Xuzhou, Jiangsu, 221116, China
| | - Yuanzhi Zhang
- Lab of Environmental Remote Sensing (LERS), School of Marine Sciences (SMS), Nanjing University of Information Science and Technology (NUIST), Nanjing, 210044, China
| | - Shamsuddin Shahid
- Department of Hydraulics & Hydrology, University Technology Malaysia, Malaysia
| | - Mansour Almazroui
- Center of Excellence for Climate Change Research/Department of Meteorology, King Abdulaziz University, Jeddah, 21589, Saudi Arabia; Climatic Research Unit, School of Environmental Sciences, University of East Anglia, Norwich, UK
| | - M Nazrul Islam
- Center of Excellence for Climate Change Research/Department of Meteorology, King Abdulaziz University, Jeddah, 21589, Saudi Arabia.
| | - Muhammad Ashfaqur Rahman
- Weather and Climate Model Earth Science Technology and Policy Services Ltd. (ESTEPS), Dhaka, 1000, Bangladesh
| | - Sanjit Kumar Mondol
- School of Geographical Science, Nanjing University of Information Science and Technology, Nanjing, 210044, China
| | | | - Khaled Mohamed Khedher
- Department of Civil Engineering, College of Engineering, King Khalid University, Abha, 61421, Saudi Arabia
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AlRayess S, Sleiman A, Alameddine I, Abou Fayad A, Matar GM, El-Fadel M. Airborne bacterial and PM characterization in intensive care units: correlations with physical control parameters. AIR QUALITY, ATMOSPHERE & HEALTH 2022; 15:1869-1880. [PMID: 35815238 PMCID: PMC9255450 DOI: 10.1007/s11869-022-01222-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 06/24/2022] [Indexed: 11/29/2022]
Abstract
In this study, the spatial variation of airborne bacteria in intensive care units (ICUs) was characterized. Fine particulate matter and several physical parameters were also monitored including temperature and relative humidity. The results showed that the total bacterial load ranged between 20.4 and 134.3 CFU/m3 across the ICUs. Bacterial cultures of the collected samples did not isolate any multi-drug-resistant Gram-negative bacilli indicating the absence of such aerosolized pathogens in the ICUs. Meanwhile, particulate matter levels in several ICUs were found to exceed the international guidelines set for 24-h PM exposure. Moreover, examining bacterial load contribution by size suggested that bacteria with sizes less than 0.65 µm contributed the least to the total bacterial loads, while those with sizes between 0.65 and 1.1 µm contributed the most. A multiple linear regression model was also built to predict the bacterial loads in the ICUs. The regression analysis explained 77% of the variability observed in the measured bacterial concentrations. The model showed that the level of activity in the ICU rooms as well as its occupancy level had strong positive correlations with bacterial loads, while distance away from the patient had a non-linear relationship with measured loads. No statistically significant correlation was found between bacterial load and particulate matter concentrations.
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Affiliation(s)
- S. AlRayess
- Department of Civil & Environmental Engineering, American University of Beirut, Beirut, Lebanon
| | - A. Sleiman
- Department of Experimental Pathology, Immunology and Microbiology, American University of Beirut, Beirut, Lebanon
- Center for Infectious Disease Research (CIDR), American University of Beirut, Beirut, Lebanon
- WHO Collaborating Center for Reference and Research On Bacterial Pathogens, Beirut, Lebanon
| | - I. Alameddine
- Department of Civil & Environmental Engineering, American University of Beirut, Beirut, Lebanon
| | - A. Abou Fayad
- Department of Experimental Pathology, Immunology and Microbiology, American University of Beirut, Beirut, Lebanon
- Center for Infectious Disease Research (CIDR), American University of Beirut, Beirut, Lebanon
- WHO Collaborating Center for Reference and Research On Bacterial Pathogens, Beirut, Lebanon
| | - G. M. Matar
- Department of Experimental Pathology, Immunology and Microbiology, American University of Beirut, Beirut, Lebanon
- Center for Infectious Disease Research (CIDR), American University of Beirut, Beirut, Lebanon
- WHO Collaborating Center for Reference and Research On Bacterial Pathogens, Beirut, Lebanon
| | - M. El-Fadel
- Department of Civil & Environmental Engineering, American University of Beirut, Beirut, Lebanon
- Department of Industrial and Systems Engineering, Khalifa University, Abu Dhabi, UAE
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Laurent MR, Frans J. Monitors to improve indoor air carbon dioxide concentrations in the hospital: A randomized crossover trial. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:151349. [PMID: 34728206 PMCID: PMC8556868 DOI: 10.1016/j.scitotenv.2021.151349] [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: 08/20/2021] [Revised: 10/02/2021] [Accepted: 10/27/2021] [Indexed: 05/30/2023]
Abstract
BACKGROUND Ventilation has emerged as an important strategy to reduce indoor aerosol transmission of coronavirus disease 2019. Indoor air carbon dioxide (CO2) concentrations are a surrogate measure of respiratory pathogen transmission risk. OBJECTIVES To determine whether CO2 monitors are necessary and effective to improve ventilation in hospitals. METHODS A randomized, placebo (sham)-controlled, crossover, open label trial. Between February and May 2021, we placed CO2 monitors in twelve double-bed patient rooms across two geriatric wards. Staff were instructed to open windows, increase the air exchange rate and reduce room crowding to maintain indoor air CO2 concentrations ≤800 parts per million (ppm). RESULTS CO2 levels increased during morning care and especially in rooms housing couples (rooming-in). The median (interquartile range, IQR) time/day with CO2 concentration > 800 ppm (primary outcome) was 110 min (IQR 47-207) at baseline, 82 min (IQR 12-226.5) during sham periods, 78 min (IQR 20-154) during intervention periods and 140 min (IQR 19.5-612.5) post-intervention. The intervention period only differed significantly from the post-intervention period (P = 0.02), mainly due to an imbalance in rooming-in. Significant but small differences were observed in secondary outcomes of time/day with CO2 concentrations > 1000 ppm and daily peak CO2 concentrations during the intervention vs. baseline and vs. the post-intervention period, but not vs. sham. Staff reported cold discomfort for patients as the main barrier towards increasing ventilation. DISCUSSION Indoor air CO2 concentrations in hospital rooms commonly peaked above recommended levels, especially during morning care and rooming-in. There are many possible barriers towards implementing CO2 monitors to improve ventilation in a real-world hospital setting. A paradigm shift in hospital infection control towards adequate ventilation is warranted. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT04770597.
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Affiliation(s)
- Michaël R Laurent
- Geriatrics Department, Imelda Hospital, Bonheiden, Belgium; Geriatrics Department, University Hospitals Leuven, Leuven, Belgium.
| | - Johan Frans
- Department of Medical Microbiology, Imelda Hospital, Bonheiden, Belgium
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Kharel M, Chalise S, Chalise B, Sharma KR, Gyawali D, Paudyal H, Neupane BB. Assessing volatile organic compound level in selected workplaces of Kathmandu Valley. Heliyon 2021; 7:e08262. [PMID: 34765781 PMCID: PMC8571507 DOI: 10.1016/j.heliyon.2021.e08262] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 10/04/2021] [Accepted: 10/22/2021] [Indexed: 01/24/2023] Open
Abstract
Volatile organic compounds (VOCs) are one of the major contributors to poor indoor air quality. Due to advancements in sensor technologies, continuous if not regular monitoring total VOC (TVOC) and or some specific VOC in potential high risk workplaces is possible even in resource limited settings. In this study, we implemented a portable VOC sensor to measure concentration of TVOC and formaldehyde (HCHO) in six types of potential high risk workplaces (n = 56 sites) of Katmandu Valley. For comparison, concentration was also measured in immediate surroundings (n = 56) of all the sites. To get preliminary information on safety practices, a survey study was also conducted. The mean TVOC and HCHO concentration in the sites ranged from 1.5‒8 mg/m3 and <0.01–5.5 mg/m3, respectively. The indoor: outdoor TVOC and HCHO ratio (I/O) was found to be significantly higher (I/O > 1.5 and p < 0.05) in 34 (~61%) and 47 sites (∼84%), respectively. A strong positive correlation between HCHO and TVOC concentration was observed in furniture industry (R = 0.91) and metal workshops (R = 0.98). Interestingly, we found TVOC and HCHO concentration higher than WHO safe limit in ∼64% and ∼32% sites, respectively. A rough estimate of chronic daily intake (CDI) of formaldehyde showed that CDI is higher than WHO limit in four sites. These findings suggested that indoor air quality in the significant number of the workplaces is poor and possible measures should be taken to minimize the exposure.
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Affiliation(s)
- Madhav Kharel
- Central Department of Chemistry, Tribhuvan University, Kathmandu, Nepal
| | - Surendra Chalise
- Central Department of Chemistry, Tribhuvan University, Kathmandu, Nepal
| | - Baburam Chalise
- Central Department of Chemistry, Tribhuvan University, Kathmandu, Nepal
| | - Khaga Raj Sharma
- Central Department of Chemistry, Tribhuvan University, Kathmandu, Nepal
| | - Deepak Gyawali
- Central Department of Chemistry, Tribhuvan University, Kathmandu, Nepal.,Ministry of Forests and Environment, Department of Environment, Government of Nepal, Nepal
| | - Hari Paudyal
- Central Department of Chemistry, Tribhuvan University, Kathmandu, Nepal
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