Hi Everyone, SOCAAR is pleased to announce our next SOCAAR Seminar: Wednesday, February 1, 2023 3:00PM - 4:00PM EDT Prof. María-Teresa Pay-Pérez Associate Professor Department of Genetic, Microbiology and Statistics University of Barcelona Visiting Professor SOCAAR – Department of Chemical Engineering and Applied Chemistry University of Toronto Ozone source apportionment over Europe It is well established that in Europe, high O3 concentrations are most pronounced in southern/Mediterranean countries due to the more favorable climatological conditions for its formation. However, the contribution of the different sources of precursors to O3 formation within each country relative to the imported (regional and hemispheric) O3 is poorly quantified. This lack of quantitative knowledge prevents local authorities from effectively designing plans that reduce the exceedances of the O3 target value set by the European Air Quality Directive. O3 source attribution is a challenge because the concentration at each location and time results not only from local biogenic and anthropogenic precursors, but also from the transport of O3 and precursors from neighboring regions, O3 regional and hemispheric transport and stratospheric O3 injections. This seminar presents the results of applying a source-oriented source apportionment method to provide an estimation of the contribution of the largest NOx national sectors to peak O3 events in southwestern Europe (targeting Spain) relative to the contribution of imported (regional and hemispheric) O3. We show, for the first time, that imported O3 is the largest input to the ground-level O3 concentration in Spain, accounting for 46 %–68 % of the daily mean O3 concentration during exceedances of the European target value. However, during stagnant conditions, the local anthropogenic precursors control the O3 peaks in areas downwind of the main urban and industrial regions (up to 40 % in hourly peaks). We also show that ground-level O3 concentrations are strongly affected by vertical mixing of O3-rich layers present in the free troposphere. Our results show O3 source apportionment to be an essential analysis prior to the design of O3 mitigation plans in any non-attainment area. Achieving the European O3 objectives in southern Europe requires not only ad hoc local actions but also decided national and European-wide strategies. Join us In Person: 200 College Street - Wallberg Building - Room 407 Or Online: Microsoft Teams meeting Join on your computer, mobile app or room device Click here to join the meeting<https://teams.microsoft.com/l/meetup-join/19%3ameeting_YTgwZmViNWMtNTkwMi00MjQzLWI2MDEtNTdkMTk5MzQ3YThj%40thread.v2/0?context=%7b%22Tid%22%3a%2278aac226-2f03-4b4d-9037-b46d56c55210%22%2c%22Oid%22%3a%2276a2f469-c5cc-446a-8132-c4bf6f5856ed%22%7d> Meeting ID: 278 486 268 190 Passcode: weFv4C Download Teams<https://www.microsoft.com/en-us/microsoft-teams/download-app> | Join on the web<https://www.microsoft.com/microsoft-teams/join-a-meeting> Or call in (audio only) +1 647-794-1609,,45383385#<tel:+16477941609,,45383385#> Canada, Toronto Phone Conference ID: 453 833 85# Find a local number<https://dialin.teams.microsoft.com/d82c5eb5-d575-428c-bac3-869ecf09d547?id=45383385> | Reset PIN<https://dialin.teams.microsoft.com/usp/pstnconferencing> Learn More<https://aka.ms/JoinTeamsMeeting> | Meeting options<https://teams.microsoft.com/meetingOptions/?organizerId=76a2f469-c5cc-446a-8132-c4bf6f5856ed&tenantId=78aac226-2f03-4b4d-9037-b46d56c55210&[log in to unmask]&messageId=0&language=en-US> ________________________________________________________________________________