EGUsphere EGUsphere EGUsphere EGUsphere Copernicus Publications Göttingen, Germany 10.5194/egusphere-2026-116 UCB-GLOBES: An open-access mass spectral database of identified and unidentified atmospheric organic compounds Yee Lindsay D. https://orcid.org/0000-0001-8965-9319 1 Franklin Emily B. https://orcid.org/0000-0002-3568-5359 2 12 Weber Robin J. 1 Zhao Jessica 3 Zhang Tiger 4 Xu Stephanie 4 Santillan Isaac 4 Li Fangyuan 5 Jen Coty N. https://orcid.org/0000-0002-3633-4614 1 13 Zhang Haofei https://orcid.org/0000-0002-7936-4493 1 14 Liang Yutong https://orcid.org/0000-0003-1372-772X 1 15 Isaacman Van-Wertz Gabriel https://orcid.org/0000-0002-3717-4798 1 16 Wernis Rebecca A. https://orcid.org/0000-0002-1001-1091 2 Offenberg John https://orcid.org/0000-0002-0213-4024 6 17 Lewandowski Michael https://orcid.org/0000-0002-0058-956X 6 20 Joo Taekyu https://orcid.org/0000-0002-8252-4232 7 18 Takeuchi Masayuki https://orcid.org/0000-0002-9327-6748 8 Eris Gamze 8 Xu Weiqi 9 19 Ng Nga L. https://orcid.org/0000-0001-8460-4765 7 8 9 Chen Yuzhi https://orcid.org/0000-0002-2547-8428 10 Shilling John E. https://orcid.org/0000-0002-3728-0195 10 Upshur Mary Alice 11 Gray Bé Ariana 11 Thomson Regan J. https://orcid.org/0000-0001-5546-4038 11 Geiger Franz M. 11 Goldstein Allen H. https://orcid.org/0000-0003-4014-4896 1 2 Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, 94720, USA Department of Civil and Environmental Engineering, University of California, Berkeley, Berkeley, 94720, USA Department of Industrial Engineering & Operations Research, University of California, Berkeley, Berkeley, 94720, USA Department of Electrical Engineering & Computer Sciences, University of California, Berkeley, Berkeley, 94720, USA Department of Statistics, University of California, Berkeley, Berkeley, 94720, USA Office of Research and Development, Center for Environmental Measurement and Modeling, Atmospheric and Environmental Systems Modeling Division, US Environmental Protection Agency, Research Triangle Park, 27711, USA School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, 30332, USA School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, 30332, USA School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, 30332, USA Atmospheric, Climate, and Earth Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA Department of Chemistry, Northwestern University, Evanston, 60208, USA now at: CSIRO Environment, Aspendale, Victoria 3195, Australia now at: Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, 15213, USA now at: Department of Chemistry, University of California, Riverside, Riverside, 92507, USA now at: Thrust of Sustainable Energy and Environment, The Hong Kong University of Science and Technology (Guangzhou), Guangdong, 511453, China now at: Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, 24060, USA present affiliation: Office of Applied Science and Environmental Solutions, Applied Science and Environmental Methods Division, US Environmental Protection Agency, Research Triangle Park, 27711, USA now at: Department of Earth and Environmental Sciences, Korea University, Seoul, 02841, South Korea now at: State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100864, China retired 05 02 2026 2026 1 34 Copyright: © 2026 Lindsay D. Yee et al. 2026 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-116/ The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-116/egusphere-2026-116.pdf

Chemical characterization of atmospheric organic aerosols using gas chromatography with 70 eV electron ionization mass spectrometry (GC/EI-MS) has been used for decades in advancing molecular marker detection and identification, though primarily through suspect screening and/or targeted analyses. To advance non-targeted analyses of environmental samples, we have catalogued approximately 27,000 mass spectra (MS) of semi-volatile organic aerosol (OA) analytes observed in ambient samples from the U.S. and the Central Amazon and/or laboratory simulations of secondary OA (SOA) formation in the open-access University of California Berkeley Goldstein Library of Organic Biogenic Environmental Spectra (UCB-GLOBES). These samples are representative of OA under urban and biomass burning influences as well as SOA derived from biogenic precursors (e.g., isoprene, monoterpenes, sesquiterpenes) and biomass burning intermediates. MS are documented in UCB-GLOBES without regard to known chemical identity, annotated with extensive metadata such as sample source/experimental conditions, structural information gained from MS analyses, and predicted chemical properties such as average carbon oxidation state and carbon number. UCB-GLOBES MS are compatible for importing into NIST MS Search program, and we have also provided a Jupyter Notebook for MS visualization and comparisons. We demonstrate the utility of UCB-GLOBES through MS reanalyses of prior analytes observed in ambient data, finding a 20 % reduction in the number of analytes assigned to OA source categories reliant solely on time series correlation and an overall 11 % increase in new MS-based OA source categorization for the Southeast U.S. For 1,513 analytes observed previously in the Central Amazon, we found 375 MS matches using UCB-GLOBES vs. 136 MS matches during prior analyses, representing a 14 % gain in newly confirmed or newly categorized OA species. While OA from laboratory oxidation experiments in UCB-GLOBES are highly diverse chemically, on average only 29 % of UCB-GLOBES MS have a mass spectral match to another MS entry in UCB-GLOBES and/or in the NIST MS Database. This indicates that roughly 70 % of UCB-GLOBES MS are unique thus far, not observed more than once among the laboratory oxidation samples and ambient data in UCB-GLOBES MS. Further, only 18 % can be positively identified in the NIST MS database or with known authentic standards. This points to a large gap between these laboratory simulations and ambient OA. Overall, the UCB-GLOBES database can be utilized for improving confidence in OA source categorization and/or identification, novel chemical marker discovery, tracking chemical diversity, <em>de novo </em>structure and properties prediction, and improving MS search and matching algorithms. inform future research priorities for the chemical characterization of atmospheric organic samples.

 U.S. Department of Energy DE-SC0020051 AC05-76 RL01830 National Science Foundation AGS-1830727 CHE-1607640 National Oceanic and Atmospheric Administration NA18OAR4310112