{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,21]],"date-time":"2026-02-21T10:52:13Z","timestamp":1771671133663,"version":"3.50.1"},"reference-count":27,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2022,5,13]],"date-time":"2022-05-13T00:00:00Z","timestamp":1652400000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"FCT\/MCTES","doi-asserted-by":"publisher","award":["LA\/P\/0064\/2020"],"award-info":[{"award-number":["LA\/P\/0064\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"FCT\/MCTES","doi-asserted-by":"publisher","award":["UIDB\/04750\/2020"],"award-info":[{"award-number":["UIDB\/04750\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"FCT\/MCTES","doi-asserted-by":"publisher","award":["LA\/P\/0064\/2020"],"award-info":[{"award-number":["LA\/P\/0064\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"FCT\/MCTES","doi-asserted-by":"publisher","award":["UIDB\/04750\/2020"],"award-info":[{"award-number":["UIDB\/04750\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJERPH"],"abstract":"<jats:p>Airborne transmission is mainly associated with poorly ventilated and crowded indoor environments where people stay for long periods of time. As such, public transport is often perceived as having a high risk for the transmission of SARS-CoV-2. Considering that data on the detection of SARS-CoV-2 in public transport systems are scarce, we performed air sampling for SARS-CoV-2 in indoor and outdoor spaces of public transport systems in Portugal. Air (n = 31) and surface (n = 70) samples were collected using a Coriolis\u00ae Compact microbial air sampler and sterile flocked plastic swabs, respectively. Samples were extracted and analyzed through RT-qPCR. Only two air samples from an outdoor and a partially open space were found to be positive for SARS-CoV-2 RNA. No positive surface samples were detected. These results indicate that the viral concentration in ambient air in public transport systems is linked to the number of people present in that environment and whether they are wearing properly fitting masks. Considering the current lifting of COVID-19 restrictions around the world, it is essential that people continue to wear masks in both indoor and outdoor environments, especially in crowded spaces. More studies on this topic are needed to fully elucidate the real risk of infection in outdoor spaces.<\/jats:p>","DOI":"10.3390\/ijerph19105955","type":"journal-article","created":{"date-parts":[[2022,5,14]],"date-time":"2022-05-14T09:27:56Z","timestamp":1652520476000},"page":"5955","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["Detection of SARS-CoV-2 in the Indoor and Outdoor Areas of Urban Public Transport Systems of Three Major Cities of Portugal in 2021"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8384-0640","authenticated-orcid":false,"given":"Priscilla Gomes","family":"da Silva","sequence":"first","affiliation":[{"name":"ICBAS\u2014Instituto de Ci\u00eancias Biom\u00e9dicas Abel Salazar, School of Medicine and Biomedical Sciences, University of Porto, 4050-313 Porto, Portugal"},{"name":"Epidemiology Research Unit (EPIUnit), Instituto de Sa\u00fade P\u00fablica, University of Porto, 4050-600 Porto, Portugal"},{"name":"Laborat\u00f3rio para a Investiga\u00e7\u00e3o Integrativa e Translacional em Sa\u00fade Populacional (ITR), 4050-313 Porto, Portugal"},{"name":"LEPABE\u2014Laborat\u00f3rio de Engenharia de Processos, Ambiente, Biotecnologia e Energia, Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2191-527X","authenticated-orcid":false,"given":"Jos\u00e9","family":"Gon\u00e7alves","sequence":"additional","affiliation":[{"name":"Department of Chemical Engineering and Environmental Technology, Institute of Sustainable Processes, University of Valladolid, 47011 Valladolid, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6157-4978","authenticated-orcid":false,"given":"Maria S\u00e3o Jos\u00e9","family":"Nascimento","sequence":"additional","affiliation":[{"name":"Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4139-673X","authenticated-orcid":false,"given":"Sofia I. V.","family":"Sousa","sequence":"additional","affiliation":[{"name":"LEPABE\u2014Laborat\u00f3rio de Engenharia de Processos, Ambiente, Biotecnologia e Energia, Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal"},{"name":"ALiCE\u2014Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8769-8103","authenticated-orcid":false,"given":"Jo\u00e3o R.","family":"Mesquita","sequence":"additional","affiliation":[{"name":"ICBAS\u2014Instituto de Ci\u00eancias Biom\u00e9dicas Abel Salazar, School of Medicine and Biomedical Sciences, University of Porto, 4050-313 Porto, Portugal"},{"name":"Epidemiology Research Unit (EPIUnit), Instituto de Sa\u00fade P\u00fablica, University of Porto, 4050-600 Porto, Portugal"},{"name":"Laborat\u00f3rio para a Investiga\u00e7\u00e3o Integrativa e Translacional em Sa\u00fade Populacional (ITR), 4050-313 Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2022,5,13]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"528","DOI":"10.1038\/s41579-021-00535-6","article-title":"Transmissibility and Transmission of Respiratory Viruses","volume":"19","author":"Leung","year":"2021","journal-title":"Nat. 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Res."}],"container-title":["International Journal of Environmental Research and Public Health"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1660-4601\/19\/10\/5955\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T23:10:37Z","timestamp":1760137837000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1660-4601\/19\/10\/5955"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,5,13]]},"references-count":27,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2022,5]]}},"alternative-id":["ijerph19105955"],"URL":"https:\/\/doi.org\/10.3390\/ijerph19105955","relation":{},"ISSN":["1660-4601"],"issn-type":[{"value":"1660-4601","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,5,13]]}}}