Online CHARON PTR-ToF-MS measurements elucidate residential heating as the major contributor of wintertime organic aerosol in Fairbanks, Alaska

• Main Authors: Ijaz, Amna, Temime-Roussel, Brice, Barret, Brice, Slimane, Bekki, Brett, Natalie, Cesler-Maloney, Meeta, Fochesatto, Javier, Chazeau, Benjamin, Savarino, Joel, Law, Kathy S., Simpson, William, d'Anna, Barbara
• Other Authors: Laboratoire Chimie de l'environnement (LCE), Aix Marseille Université (AMU)-Institut de Chimie - CNRS Chimie (INC-CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'aérologie (LAERO), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS), STRATO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), TROPO - LATMOS, Department of Chemistry and Biochemistry Fairbanks, University of Alaska Fairbanks (UAF), Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2024
• Subjects: [SDE]Environmental Sciences; Arctic; Fairbanks; Alaska
• Online Access: https://insu.hal.science/insu-04508001; https://insu.hal.science/insu-04508001/document; https://insu.hal.science/insu-04508001/file/EGU24-11073-print.pdf; https://doi.org/10.5194/egusphere-egu24-11073

International audience Fairbanks, central Alaska, is a sub-Arctic city that frequently suffers from non-attainment of national air quality standards in the wintertime due to the coincidence of weak atmospheric dispersion and increased local emissions but large uncertainties exist about aerosol sources and formation. We determined the general composition and mass concentrations of atmospheric sub-micron non-refractory particulate matter (NR-PM­1) and quantified the sources involved in its formation during a 6-week campaign in the urban centre of Fairbanks in January-February 2022. As part of the Alaskan Layered Pollution and Chemical Analysis campaign (ALPACA), we deployed a Chemical Analysis of Aerosol Online (CHARON) inlet coupled with a proton transfer reaction - time of flight mass spectrometer (PTR-ToF 6000 Ionicon Analytik) and high-resolution aerosol mass spectrometer (HR-ToF-AMS Aerodyne) to measure organic aerosol (OA) and NR-PM1, respectively, with high temporal resolution of ≤1 min. We performed positive matrix factorisation (PMF) of the measurements to apportion aerosol mass to potential sources. The ability of HR-ToF-AMS to measure inorganic species (ammonium, nitrates, sulphates, and chlorides) creates an opportunity to gain insights into their mixing with OA and chemical dynamics. Campaign-averages of OA measured with the two instruments agreed reasonably well (R2 = 0.60) with a regression slope of 0.46. Higher OA concentrations observed with the HR-ToF-AMS are attributable to the particle size-dependence of the CHARON inlet, since it is more sensitive to particles >150 nm; a regression slope approaching 1.0 was achieved for larger primary OA emissions from biomass burning. On the one hand, in line with known emission patterns in Fairbanks, PMF indicated residential heating (Res-H) to be the single largest source of OA here during the wintertime as per CHARON PTR-ToF-MS measurements. A large fraction of OA originated from the combustion of different types of wood (2.07 ± 2.47 µg/m3; 47.15 ± ...