12:45pm - 1:00pmFR2-5: 1
Impact of forest management on biogenic volatile organic compounds emission and secondary organic aerosol formation from a boreal forest
Yiwei Gong1, Cheng Wu2,3,4, Radovan Krejci3,4, Claudia Mohr1,3,4,5
1Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland; 2Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden; 3Department of Environmental Science, Stockholm University, Stockholm, Sweden; 4Bolin Centre for Climate Research, Stockholm University, 11418 Stockholm, Sweden; 5Department of Environmental System Science, ETH Zürich, 8006 Zürich, Switzerland
Approximately 2% of the managed forest in Sweden is harvested annually. Our research captured a clearcutting event in 2022 at the Norunda station in Swedish boreal forest. During clearcutting, an increase in monoterpene concentration to over 60 ppb was observed. Sesquiterpene and diterpene showed diurnal patterns similar to that of monoterpene in pre-, during, and post-cutting periods. Isoprene did not show a significant increase. The cutting event altered the ratios of different BVOC, which further influenced the SOA formation. Higher signals of particulate organic compounds were observed during cutting. BVOC showed varying contributions to SOA compositions across different periods.
1:00pm - 1:15pmFR2-5: 2
The fate of organic aerosol in the presence of fog in the Italian Po Valley
Yvette Gramlich1, Fredrik Mattsson2,3, Sophie L. Haslett2,3, Liine Heikkinen2,3, Almuth Neuberger2,3, Marco Paglinoe4, Matteo Rinaldi4, Jing Cai5,6, Nora Zannoni4, Angela Marinoni4, Sarah Steimer2,3, Ilona Riipinen2,3, Paul Zieger2,3, Stefano Decesari4, Claudia Mohr1,7
1PSI Center for Energy and Environmental Sciences, 5232 Villigen PSI, Switzerland; 2Department of Environmental Science, Stockholm University, 11418 Stockholm, Sweden; 3Bolin Centre for Climate Research, Stockholm University, 11418 Stockholm, Sweden; 4Italian National Research Council-Institute of Atmospheric Sciences and Climate, 40129 Bologna, Italy; 5Institute for Atmospheric and Earth System Research, University of Helsinki, 00014 Helsinki, Finland; 6Nanjing University of Information Science & Technology, China; 7Department of Environmental Systems Science, ETH Zürich, 8006 Zürich, Switzerland
The Po Valley in Italy is a hotspot of pollution in Europe. In winter radiation fog occurs and affects the air composition, where gas-phase changes of organic aerosol are understudied. During in-situ observations in winter/spring 2021/2022 we analyzed the molecular-level chemical composition changes of organic aerosol in the gas and particle phase in the presence of fog, using mass spectrometry. Preliminary results show changes in the volatility distributions for both phases, suggesting scavenging by the droplets and phase partitioning. The study helps to establish a better assessment of aerosol-fog interactions on human health and climate in polluted regions.
1:15pm - 1:30pmFR2-5: 3
Characterization of Secondary Organic Aerosols in an urban forest in São Paulo, Brazil, using CHARON-PTR-ToF-MS.
Olatunde Murana1, Sebastien Dusanter1, Joel F. de Brito1, Marina Jamar1, Veronique Riffault1, Adalgiza Fornaro2, Agnes Borbon3
1IMT Nord Europe, Institut Mines-Télécom, Univ. Lille, Centre for Energy and Environment, 59000, Lille, France;; 2Dept. Ciências Atmosféricas, Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Univ. São Paulo (IAG-USP), 05508-090, Brazil;; 3Univ: Clermont Auvergne, CNRS, LaMP, OPGC, F-63000, Clermont-Ferrand, France
This study investigates secondary organic aerosol (SOA) formation in São Paulo, a megacity influenced by both biogenic and anthropogenic emissions. Field measurements during the BIOMASP+ campaign (April-May 2023) were combined with chamber experiments to study VOC oxidation and SOA composition. Using CHARON-PTR-ToF-MS, the average SOA concentration was 4.5 µg m⁻³, with CxHyO2, CxHyO3, and CxHyO4 compounds contributing most. High-NOx isoprene markers, linked to polluted conditions, dominated, while low-NOx epoxydiol products were scarce. This research enhances understanding of SOA formation mechanisms in biogenically influenced urban areas, supporting improved air quality management in complex urban environments like São Paulo.
1:30pm - 1:45pmFR2-5: 4
Molecular Insights into Seasonal Trends in Organic Gases and Particle in a Polluted Megacity: From Anthropogenic to Biogenic emissions
LU QI1,2, Zhenzhen Niu3, ChuanPing Lee2, Liwei Wang2, Shaofei Kong3, Qiyuan Wang4, Junji Cao5, Andre Prevot2, Jay Slowik2
1Institute for Atmospheric and Earth System Research (INAR), University of Helsinki, Finland; 2Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen PSI, Switzerland; 3Department of Atmospheric Sciences, China University of Geosciences, Wuhan, China; 4Institute of Earth Environment, Chinese Academy of Sciences, Xi’an, China; 5Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
The study investigates the seasonal transition of organic gases and particles in a polluted megcity, focusing on secondary organic aerosol (SOA) formation at molecular level. Using advanced mass spectrometry techniques, the research captures shifts from winter heating emissions to biogenic sources in spring. It highlights how volatile organic compounds (VOCs) and SOA compositions change with pollution levels and seasonal influences. Key findings include the transition from biomass burning SOA (BBOA) to biogenic SOA (BSOA) and the distinct role of fresh emissions. The study underscores the importance of co-located gas and particle-phase measurements in understanding complex atmospheric processes.
1:45pm - 2:00pmFR2-5: 5
Tracking the Aging of Biomass Burning Organic Aerosols: Molecular Insights from Punjab’s Stubble Fires and Their Implications for South Asia’s Haze
Yufang Hao1, Vikas Goel2, Anjanay Pandey3, Ajit Kumar3, Mohammad Faisal1,3, Umer Ali2, Abhishek Kumar Upadhyay1, Peeyush Khare1, Manos Manousakas1, Jens Top1, Mihnea Surdu1, David Bell1, Lu Liu1, Siyao Yue1, Qizhi Xu1, Imtiaz Ahmed4, Rishabh Singh4, Padam .4, Sumit Kumar Mishra4, Mayank Kumar2, Vikram Singh3, Jay Gates Slowik1, Imad El Haddad1, Andre Prevot1, Kaspar Rudolf Dällenbach1
1Paul Scherre Institute, Switzerland; 2Department of Mechanical Engineering, Indian Institute of Technology Delhi, New Delhi, India; 3Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi, India; 4Academy of Scientific and Innovative Research (AcSIR), India
Biomass burning is a major source of PM₂.₅, significantly impacting air quality and SOA formation. This study investigates the molecular evolution of biomass burning OA (BBOA) through a field campaign in Punjab, integrating EESI-TOF and Orbitrap MS for high-resolution analysis. Fresh BBOA showed higher CHN compounds, while aged samples were enriched in unsaturated CHO species. Clustering analysis identified key molecular tracers increasing with aging. These findings support a molecular-tracer-based SOA estimation framework, enhancing assessments of smoke plume impacts on urban air pollution in South Asia.
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