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Ebrahimifakhar A, Poursadegh M, Hu Y, Yuill DP, Luo Y. A systematic review and meta-analysis of field studies of portable air cleaners: Performance, user behavior, and by-product emissions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:168786. [PMID: 38008326 DOI: 10.1016/j.scitotenv.2023.168786] [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: 08/25/2023] [Revised: 11/08/2023] [Accepted: 11/20/2023] [Indexed: 11/28/2023]
Abstract
Indoor air quality is important for the health of building occupants, and public interest in controlling indoor airborne pathogens increased dramatically with the COVID-19 pandemic. Pollutant concentrations can be controlled locally using portable air cleaners (sometimes called air purifiers), which allow occupants to apply air cleaning technology to meet their needs in the location and times that they find appropriate. This paper provides a systematic review of scientific literature that describes field studies of the effectiveness of portable air cleaners. Over 500 papers were considered, and 148 were reviewed in detail, to extract 35 specific research results (e.g., particulate removal performance) or characteristics (e.g., type of building). These were aggregated to provide an overview of results and approaches to this type of research, and to provide meta-analyses of the results. The review includes: descriptions of the geographical location of the research; rate of publications over time; types of buildings and occupants in the field study; types of air cleaner technology being tested; pollutants being measured; resulting pollutant removal effectiveness; patterns of usage and potential barriers to usage by occupants; and the potential for by-product emissions in some air cleaner technologies. An example result is that 83 of the 148 papers measured reductions in fine particulates (PM2.5) and found a mean reduction of 49 % with standard deviation of 20 %. The aggregated results were approximately normally distributed, ranging from finding no significant reduction up to a maximum above 90 % reduction. Sixteen of the 148 papers considered gaseous pollutants, such as volatile organic compounds, nitrogen dioxide, and ozone; 36 papers considered biological pollutants, such as bacteria, viruses, pollen, fungi, etc. An important challenge, common to several studies, is that occupants run the air cleaners for shorter periods and on low airflow rate settings, because of concerns about noise, drafts, and electricity cost, which significantly reduces air cleaning effectiveness.
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Affiliation(s)
- Amir Ebrahimifakhar
- Delos Labs, Delos, New York, NY 10014, USA; Durham School of Architectural Engineering and Construction, University of Nebraska - Lincoln, 1110 S. 67th Street, Omaha, NE 68182, USA.
| | - Mehrdad Poursadegh
- Durham School of Architectural Engineering and Construction, University of Nebraska - Lincoln, 1110 S. 67th Street, Omaha, NE 68182, USA.
| | - Yifeng Hu
- Durham School of Architectural Engineering and Construction, University of Nebraska - Lincoln, 1110 S. 67th Street, Omaha, NE 68182, USA; Buildings and Transportation Science Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA.
| | - David P Yuill
- Durham School of Architectural Engineering and Construction, University of Nebraska - Lincoln, 1110 S. 67th Street, Omaha, NE 68182, USA.
| | - Yu Luo
- Department of Applied Physics and Applied Mathematics, Columbia University, 500 W. 120th Street, New York, NY 10027, USA.
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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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Myers NT, Laumbach RJ, Black KG, Ohman‐Strickland P, Alimokhtari S, Legard A, De Resende A, Calderón L, Lu FT, Mainelis G, Kipen HM. Portable air cleaners and residential exposure to SARS-CoV-2 aerosols: A real-world study. INDOOR AIR 2022; 32:e13029. [PMID: 35481935 PMCID: PMC9111720 DOI: 10.1111/ina.13029] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 03/22/2022] [Accepted: 04/02/2022] [Indexed: 05/04/2023]
Abstract
Individuals with COVID-19 who do not require hospitalization are instructed to self-isolate in their residences. Due to high secondary infection rates in household members, there is a need to understand airborne transmission of SARS-CoV-2 within residences. We report the first naturalistic intervention study suggesting a reduction of such transmission risk using portable air cleaners (PACs) with HEPA filters. Seventeen individuals with newly diagnosed COVID-19 infection completed this single-blind, crossover, randomized study. Total and size-fractionated aerosol samples were collected simultaneously in the self-isolation room with the PAC (primary) and another room (secondary) for two consecutive 24-h periods, one period with HEPA filtration and the other with the filter removed (sham). Seven out of sixteen (44%) air samples in primary rooms were positive for SARS-CoV-2 RNA during the sham period. With the PAC operated at its lowest setting (clean air delivery rate [CADR] = 263 cfm) to minimize noise, positive aerosol samples decreased to four out of sixteen residences (25%; p = 0.229). A slight decrease in positive aerosol samples was also observed in the secondary room. As the world confronts both new variants and limited vaccination rates, our study supports this practical intervention to reduce the presence of viral aerosols in a real-world setting.
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Affiliation(s)
- Nirmala T. Myers
- Department of Environmental SciencesRutgers UniversityNew BrunswickNew JerseyUSA
- Rutgers Environmental and Occupational Health Sciences InstituteRutgers UniversityPiscatawayNew JerseyUSA
| | - Robert J. Laumbach
- Rutgers Environmental and Occupational Health Sciences InstituteRutgers UniversityPiscatawayNew JerseyUSA
- Department of Environmental and Occupational Health and JusticeRutgers UniversityPiscatawayNew JerseyUSA
| | - Kathleen G. Black
- Rutgers Environmental and Occupational Health Sciences InstituteRutgers UniversityPiscatawayNew JerseyUSA
| | - Pamela Ohman‐Strickland
- Rutgers Environmental and Occupational Health Sciences InstituteRutgers UniversityPiscatawayNew JerseyUSA
- Department of Biostatistics and EpidemiologyRutgers School of Public HealthRutgers UniversityPiscatawayNew JerseyUSA
| | - Shahnaz Alimokhtari
- Rutgers Environmental and Occupational Health Sciences InstituteRutgers UniversityPiscatawayNew JerseyUSA
| | - Alicia Legard
- Rutgers Environmental and Occupational Health Sciences InstituteRutgers UniversityPiscatawayNew JerseyUSA
| | - Adriana De Resende
- Rutgers Environmental and Occupational Health Sciences InstituteRutgers UniversityPiscatawayNew JerseyUSA
| | - Leonardo Calderón
- Department of Environmental SciencesRutgers UniversityNew BrunswickNew JerseyUSA
- Rutgers Environmental and Occupational Health Sciences InstituteRutgers UniversityPiscatawayNew JerseyUSA
| | - Frederic T. Lu
- Rutgers Environmental and Occupational Health Sciences InstituteRutgers UniversityPiscatawayNew JerseyUSA
| | - Gediminas Mainelis
- Department of Environmental SciencesRutgers UniversityNew BrunswickNew JerseyUSA
- Rutgers Environmental and Occupational Health Sciences InstituteRutgers UniversityPiscatawayNew JerseyUSA
| | - Howard M. Kipen
- Rutgers Environmental and Occupational Health Sciences InstituteRutgers UniversityPiscatawayNew JerseyUSA
- Department of Environmental and Occupational Health and JusticeRutgers UniversityPiscatawayNew JerseyUSA
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Newman JD, Bhatt DL, Rajagopalan S, Balmes JR, Brauer M, Breysse PN, Brown AGM, Carnethon MR, Cascio WE, Collman GW, Fine LJ, Hansel NN, Hernandez A, Hochman JS, Jerrett M, Joubert BR, Kaufman JD, Malik AO, Mensah GA, Newby DE, Peel JL, Siegel J, Siscovick D, Thompson BL, Zhang J, Brook RD. Cardiopulmonary Impact of Particulate Air Pollution in High-Risk Populations: JACC State-of-the-Art Review. J Am Coll Cardiol 2020; 76:2878-2894. [PMID: 33303078 PMCID: PMC8040922 DOI: 10.1016/j.jacc.2020.10.020] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/24/2020] [Accepted: 10/12/2020] [Indexed: 12/29/2022]
Abstract
Fine particulate air pollution <2.5 μm in diameter (PM2.5) is a major environmental threat to global public health. Multiple national and international medical and governmental organizations have recognized PM2.5 as a risk factor for cardiopulmonary diseases. A growing body of evidence indicates that several personal-level approaches that reduce exposures to PM2.5 can lead to improvements in health endpoints. Novel and forward-thinking strategies including randomized clinical trials are important to validate key aspects (e.g., feasibility, efficacy, health benefits, risks, burden, costs) of the various protective interventions, in particular among real-world susceptible and vulnerable populations. This paper summarizes the discussions and conclusions from an expert workshop, Reducing the Cardiopulmonary Impact of Particulate Matter Air Pollution in High Risk Populations, held on May 29 to 30, 2019, and convened by the National Institutes of Health, the U.S. Environmental Protection Agency, and the U.S. Centers for Disease Control and Prevention.
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Affiliation(s)
- Jonathan D Newman
- Division of Cardiology and the Center for the Prevention of Cardiovascular Disease, New York University Grossman School of Medicine, New York, New York, USA.
| | - Deepak L Bhatt
- Brigham and Women's Hospital Heart and Vascular Center and Harvard Medical School, Boston, Massachusetts, USA. https://twitter.com/DLBhattMD
| | - Sanjay Rajagopalan
- Harrington Heart and Vascular Institute, University Hospitals, Case Western Reserve University, Cleveland, Ohio, USA
| | - John R Balmes
- Division of Pulmonary, Critical Care, Allergy and Sleep Medicine, Department of Medicine, University of California, San Francisco, California, USA
| | - Michael Brauer
- School of Population and Public Health, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Patrick N Breysse
- National Center for Environmental Health/Agency for Toxic Substances and Disease Registry, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Alison G M Brown
- Division of Cardiovascular Sciences, National Heart, Lung, and Blood Institute, Washington, DC, USA
| | - Mercedes R Carnethon
- Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Wayne E Cascio
- Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Durham, North Carolina, USA
| | - Gwen W Collman
- National Institute of Environmental Health Sciences, Durham, North Carolina, USA
| | - Lawrence J Fine
- Division of Cardiovascular Sciences, National Heart, Lung, and Blood Institute, Washington, DC, USA
| | - Nadia N Hansel
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Adrian Hernandez
- Clinical Research, Duke University School of Medicine, Durham, North Carolina, USA
| | - Judith S Hochman
- New York University Grossman School of Medicine, New York, New York, USA
| | - Michael Jerrett
- Fielding School of Public Health, University of California, Los Angeles, California, USA
| | - Bonnie R Joubert
- Population Health Branch, Division of Extramural Research and Training, National Institute of Environmental Health Sciences, Durham, North Carolina, USA
| | - Joel D Kaufman
- Departments of Environmental & Occupational Health Sciences, Medicine, and Epidemiology, University of Washington, Seattle, Washington, USA
| | - Ali O Malik
- Saint Luke's Mid America Heart Institute, Kansas City, Missouri, USA
| | - George A Mensah
- Center for Translation Research and Implementation Science, National Heart, Lung, and Blood Institute, Washington, DC, USA
| | - David E Newby
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
| | - Jennifer L Peel
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Jeffrey Siegel
- Department of Civil and Mineral Engineering, and the Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - David Siscovick
- Division of Research, Evaluation, and Policy, The New York Academy of Medicine, New York, New York, USA
| | - Betsy L Thompson
- Division for Heart Disease and Stroke Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Junfeng Zhang
- Nicholas School of the Environment & Duke Global Health Institute, Duke University, Durham, North Carolina, USA
| | - Robert D Brook
- Division of Cardiovascular Diseases, Wayne State University, Detroit, Michigan, USA
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Newman JD, Rajagopalan S, Levy P, Brook RD. Clearing the air to treat hypertension. J Hum Hypertens 2020; 34:759-763. [PMID: 32439971 PMCID: PMC7665990 DOI: 10.1038/s41371-020-0358-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/11/2020] [Accepted: 05/13/2020] [Indexed: 12/27/2022]
Affiliation(s)
- Jonathan D Newman
- Division of Cardiology and the Center for the Prevention of Cardiovascular Disease, New York University Grossman School of Medicine, New York, NY, USA
| | - Sanjay Rajagopalan
- Division of Cardiovascular Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Phillip Levy
- Department of Emergency Medicine, Wayne State University, Detroit, MI, USA
| | - Robert D Brook
- Division of Cardiovascular Medicine, University of Michigan, New York, NY, USA.
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