Modelling the Contribution of Factors Influencing the Risk of SARS-CoV-2 Infection in Indoor Environments
Autor(a) principal: | |
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Data de Publicação: | 2021 |
Outros Autores: | |
Tipo de documento: | Artigo |
Idioma: | por eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | https://www.actamedicaportuguesa.com/revista/index.php/amp/article/view/15982 |
Resumo: | Introduction: This study estimates the risk of aerosol infection by SARS-CoV-2 in indoor environments where high density of occupation results in an increased probability of infection, such as schools, offices, supermarkets, restaurants and gyms.Material and Methods: In each type of building use, several conditions were simulated, such as the use and effectiveness of masks, ventilation, use of equipment that allows air asepsis using HEPA filters, the density of occupancy and the length of stay in the spaces, using a model based on the dispersion of aerosol particles in indoor spaces and on the accumulation and inhalation of these particles over time.Results: The results showed that the replacement of social masks by masks with FFP2 classification decreased the risk of infection by 90% in schools. In schools with natural ventilation, the complete opening of windows reduced the risk of infection by 64% in comparison with the scenario with closed windows. In spaces where mechanical ventilation is normally used, the probability of infection decreased significantly when the regulatory fresh air flow rates were doubled (reduction of 32% in offices, 42% in restaurants, 24% in supermarkets and 46% in gyms). The filtration of air with HEPA filters allowed the reduction of the probability of infection by 72% in schools, offices, and restaurants and 61% in gyms. The length of stay in the spaces was also a relevant factor in the variation of the probability of infection, especially in schools where it was found that shorter classes with a higher number of intervals reduced the risk of infection.Discussion: The results show the importance of adequate ventilation in indoor environments, especially in places where the density of occupation and the staying times are longer, making the introduction of outside air inside the spaces essential, either through natural or mechanical means. It is expected that the infection risk estimates presented are undervalued because the model only considers transmission by particles smaller than 10 μm and does not include the short-range transmission by assuming social distancing. Vaccination was not considered in the model since it was not yet available when the study was carried out.Conclusion: The present study contributes to the identification of measures that decrease the risk of viral transmission, and consequently provide greater security in indoor spaces. |
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Modelling the Contribution of Factors Influencing the Risk of SARS-CoV-2 Infection in Indoor EnvironmentsModelação da Contribuição de Fatores Influenciadores do Risco de Infeção por SARS-CoV-2 em Ambientes InterioresAerosolsAir PollutionIndoorCOVID-19Risk FactorsSARS-CoV-2VentilationAerossóisCOVID-19Fatores de RiscoQualidade do Ar InteriorSARS-CoV-2VentilaçãoIntroduction: This study estimates the risk of aerosol infection by SARS-CoV-2 in indoor environments where high density of occupation results in an increased probability of infection, such as schools, offices, supermarkets, restaurants and gyms.Material and Methods: In each type of building use, several conditions were simulated, such as the use and effectiveness of masks, ventilation, use of equipment that allows air asepsis using HEPA filters, the density of occupancy and the length of stay in the spaces, using a model based on the dispersion of aerosol particles in indoor spaces and on the accumulation and inhalation of these particles over time.Results: The results showed that the replacement of social masks by masks with FFP2 classification decreased the risk of infection by 90% in schools. In schools with natural ventilation, the complete opening of windows reduced the risk of infection by 64% in comparison with the scenario with closed windows. In spaces where mechanical ventilation is normally used, the probability of infection decreased significantly when the regulatory fresh air flow rates were doubled (reduction of 32% in offices, 42% in restaurants, 24% in supermarkets and 46% in gyms). The filtration of air with HEPA filters allowed the reduction of the probability of infection by 72% in schools, offices, and restaurants and 61% in gyms. The length of stay in the spaces was also a relevant factor in the variation of the probability of infection, especially in schools where it was found that shorter classes with a higher number of intervals reduced the risk of infection.Discussion: The results show the importance of adequate ventilation in indoor environments, especially in places where the density of occupation and the staying times are longer, making the introduction of outside air inside the spaces essential, either through natural or mechanical means. It is expected that the infection risk estimates presented are undervalued because the model only considers transmission by particles smaller than 10 μm and does not include the short-range transmission by assuming social distancing. Vaccination was not considered in the model since it was not yet available when the study was carried out.Conclusion: The present study contributes to the identification of measures that decrease the risk of viral transmission, and consequently provide greater security in indoor spaces.Introdução: O presente trabalho estima o risco de infeção por SARS-CoV-2 em ambientes interiores onde a elevada densidade de ocupação resulta numa probabilidade acrescida de contágio, como escolas, escritórios, supermercados, restaurantes e ginásios.Material e Métodos: Foram testadas várias condições nos espaços interiores, tais como a utilização e eficácia de máscaras, a ventilação, a utilização de equipamentos que permitem uma assepsia do ar recorrendo a filtros HEPA, a densidade de ocupação e o tempo de permanência nos espaços, tendo sido utilizado um modelo baseado na dispersão de partículas de aerossóis em espaços fechados e na acumulação e inalação destas partículas ao longo do tempo.Resultados: Os resultados mostraram que a substituição de máscaras sociais por máscaras com classificação FFP2 diminuiu o risco de infeção em 90% nas escolas. Em escolas com ventilação natural, a abertura das janelas na sua totalidade reduziu o risco de infeção em 64% comparativamente com o cenário de janelas fechadas. Nos espaços onde a ventilação mecânica é normalmente utilizada, a probabilidade de infeção reduziu significativamente quando os caudais de ar novo regulamentares foram duplicados (redução de 32% nos escritórios, 42% nos restaurantes, 24% nos supermercados e 46% nos ginásios). A filtragem de ar com filtros HEPA permitiu a redução da probabilidade de infeção em 72% nas escolas, escritórios e restaurantes e 61% nos ginásios. O tempo de permanência nos espaços foi também um fator relevante na variação da probabilidade de infeção, principalmente nas escolas onde se verificou que aulas mais curtas e com um maior número de intervalos reduzem o risco de infeção.Discussão: Os resultados evidenciam a importância de uma adequada ventilação em ambientes fechados, principalmente em locais onde a densidade de ocupação e os tempos de permanência são mais longos, sendo essencial a introdução de ar exterior no interior dos espaços, seja através de meios naturais ou mecânicos. É expectável que os valores de risco de infeção apresentados ao longo do trabalho estejam subvalorizados pelo facto do modelo utilizado apenas considerar a transmissão por partículas inferiores a 10 μm e por, ao assumir o distanciamento social, não incluir a transmissão de curto alcance. A vacinação não foi considerada no modelo pelo facto de ainda não estar disponível quando o trabalho foi realizado.Conclusão: Este estudo vem contribuir para a identificação de medidas que permitem um menor risco de transmissão viral, e consequentemente, uma maior segurança no interior dos espaços fechados.Ordem dos Médicos2021-12-02info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfapplication/pdfapplication/pdfhttps://www.actamedicaportuguesa.com/revista/index.php/amp/article/view/15982Acta Médica Portuguesa; Vol. 34 No. 12 (2021): Dezembro; 815-825Acta Médica Portuguesa; Vol. 34 N.º 12 (2021): Dezembro; 815-8251646-07580870-399Xreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAPporenghttps://www.actamedicaportuguesa.com/revista/index.php/amp/article/view/15982https://www.actamedicaportuguesa.com/revista/index.php/amp/article/view/15982/6480https://www.actamedicaportuguesa.com/revista/index.php/amp/article/view/15982/15205https://www.actamedicaportuguesa.com/revista/index.php/amp/article/view/15982/6481Direitos de Autor (c) 2021 Acta Médica Portuguesainfo:eu-repo/semantics/openAccessAlmeida, Susana MartaSousa, João2023-07-23T03:00:58Zoai:ojs.www.actamedicaportuguesa.com:article/15982Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T16:20:42.563031Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Modelling the Contribution of Factors Influencing the Risk of SARS-CoV-2 Infection in Indoor Environments Modelação da Contribuição de Fatores Influenciadores do Risco de Infeção por SARS-CoV-2 em Ambientes Interiores |
title |
Modelling the Contribution of Factors Influencing the Risk of SARS-CoV-2 Infection in Indoor Environments |
spellingShingle |
Modelling the Contribution of Factors Influencing the Risk of SARS-CoV-2 Infection in Indoor Environments Almeida, Susana Marta Aerosols Air Pollution Indoor COVID-19 Risk Factors SARS-CoV-2 Ventilation Aerossóis COVID-19 Fatores de Risco Qualidade do Ar Interior SARS-CoV-2 Ventilação |
title_short |
Modelling the Contribution of Factors Influencing the Risk of SARS-CoV-2 Infection in Indoor Environments |
title_full |
Modelling the Contribution of Factors Influencing the Risk of SARS-CoV-2 Infection in Indoor Environments |
title_fullStr |
Modelling the Contribution of Factors Influencing the Risk of SARS-CoV-2 Infection in Indoor Environments |
title_full_unstemmed |
Modelling the Contribution of Factors Influencing the Risk of SARS-CoV-2 Infection in Indoor Environments |
title_sort |
Modelling the Contribution of Factors Influencing the Risk of SARS-CoV-2 Infection in Indoor Environments |
author |
Almeida, Susana Marta |
author_facet |
Almeida, Susana Marta Sousa, João |
author_role |
author |
author2 |
Sousa, João |
author2_role |
author |
dc.contributor.author.fl_str_mv |
Almeida, Susana Marta Sousa, João |
dc.subject.por.fl_str_mv |
Aerosols Air Pollution Indoor COVID-19 Risk Factors SARS-CoV-2 Ventilation Aerossóis COVID-19 Fatores de Risco Qualidade do Ar Interior SARS-CoV-2 Ventilação |
topic |
Aerosols Air Pollution Indoor COVID-19 Risk Factors SARS-CoV-2 Ventilation Aerossóis COVID-19 Fatores de Risco Qualidade do Ar Interior SARS-CoV-2 Ventilação |
description |
Introduction: This study estimates the risk of aerosol infection by SARS-CoV-2 in indoor environments where high density of occupation results in an increased probability of infection, such as schools, offices, supermarkets, restaurants and gyms.Material and Methods: In each type of building use, several conditions were simulated, such as the use and effectiveness of masks, ventilation, use of equipment that allows air asepsis using HEPA filters, the density of occupancy and the length of stay in the spaces, using a model based on the dispersion of aerosol particles in indoor spaces and on the accumulation and inhalation of these particles over time.Results: The results showed that the replacement of social masks by masks with FFP2 classification decreased the risk of infection by 90% in schools. In schools with natural ventilation, the complete opening of windows reduced the risk of infection by 64% in comparison with the scenario with closed windows. In spaces where mechanical ventilation is normally used, the probability of infection decreased significantly when the regulatory fresh air flow rates were doubled (reduction of 32% in offices, 42% in restaurants, 24% in supermarkets and 46% in gyms). The filtration of air with HEPA filters allowed the reduction of the probability of infection by 72% in schools, offices, and restaurants and 61% in gyms. The length of stay in the spaces was also a relevant factor in the variation of the probability of infection, especially in schools where it was found that shorter classes with a higher number of intervals reduced the risk of infection.Discussion: The results show the importance of adequate ventilation in indoor environments, especially in places where the density of occupation and the staying times are longer, making the introduction of outside air inside the spaces essential, either through natural or mechanical means. It is expected that the infection risk estimates presented are undervalued because the model only considers transmission by particles smaller than 10 μm and does not include the short-range transmission by assuming social distancing. Vaccination was not considered in the model since it was not yet available when the study was carried out.Conclusion: The present study contributes to the identification of measures that decrease the risk of viral transmission, and consequently provide greater security in indoor spaces. |
publishDate |
2021 |
dc.date.none.fl_str_mv |
2021-12-02 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
https://www.actamedicaportuguesa.com/revista/index.php/amp/article/view/15982 |
url |
https://www.actamedicaportuguesa.com/revista/index.php/amp/article/view/15982 |
dc.language.iso.fl_str_mv |
por eng |
language |
por eng |
dc.relation.none.fl_str_mv |
https://www.actamedicaportuguesa.com/revista/index.php/amp/article/view/15982 https://www.actamedicaportuguesa.com/revista/index.php/amp/article/view/15982/6480 https://www.actamedicaportuguesa.com/revista/index.php/amp/article/view/15982/15205 https://www.actamedicaportuguesa.com/revista/index.php/amp/article/view/15982/6481 |
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Direitos de Autor (c) 2021 Acta Médica Portuguesa info:eu-repo/semantics/openAccess |
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Direitos de Autor (c) 2021 Acta Médica Portuguesa |
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openAccess |
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application/pdf application/pdf application/pdf |
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Ordem dos Médicos |
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Ordem dos Médicos |
dc.source.none.fl_str_mv |
Acta Médica Portuguesa; Vol. 34 No. 12 (2021): Dezembro; 815-825 Acta Médica Portuguesa; Vol. 34 N.º 12 (2021): Dezembro; 815-825 1646-0758 0870-399X reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação instacron:RCAAP |
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Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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RCAAP |
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RCAAP |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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