biostudies-literatureUnknownTonne C<h4>Introduction</h4>Evidence from epidemiological studies based on individual-level data indicates that air pollution may be associated with coronavirus disease 2019 (COVID-19) severity. We aimed to test whether (1) long-term exposure to air pollution is associated with COVID-19-related hospital admission or mortality in the general population; (2) short-term exposure to air pollution is associated with COVID-19-related hospital admission following COVID-19 diagnosis; (3) there are vulnerable population subgroups; and (4) the influence of long-term air pollution exposure on COVID-19-related hospital admissions differed from that for other respiratory infections.<h4>Methods</h4>We constructed a cohort covering nearly the full population of Catalonia through registry linkage, with follow- uResearch report (Health Effects Institute)1-48https://www.ebi.ac.uk/biostudies/studies/S-EPMC11525941biostudies-literatureAir Pollution in Relation to COVID-19 Morbidity and Mortality: A Large Population-Based Cohort Study in Catalonia, Spain (COVAIR-CAT).PMC11525941Foraster MAlari ARico AValentin AMila CDadvand PDuarte TOlmos SSunyer JChaccour CBallester JRanzani OVivanco RNieuwenhuijsen MJTonne CBasagana XfalseAir Pollution in Relation to COVID-19 Morbidity and Mortality: A Large Population-Based Cohort Study in Catalonia, Spain (COVAIR-CAT).<h4>Introduction</h4>Evidence from epidemiological studies based on individual-level data indicates that air pollution may be associated with coronavirus disease 2019 (COVID-19) severity. We aimed to test whether (1) long-term exposure to air pollution is associated with COVID-19-related hospital admission or mortality in the general population; (2) short-term exposure to air pollution is associated with COVID-19-related hospital admission following COVID-19 diagnosis; (3) there are vulnerable population subgroups; and (4) the influence of long-term air pollution exposure on COVID-19-related hospital admissions differed from that for other respiratory infections.<h4>Methods</h4>We constructed a cohort covering nearly the full population of Catalonia through registry linkage, with follow- u2024-01-01T00:00:00Z2024 Sep2025-04-04T09:59:07.271Z2025-04-04T09:59:07.271ZS-EPMC1152594139468856