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Neukirchen C, Meiners T, Bendl J, Zimmermann R, Adam T. Automated SEM/EDX imaging for the in-depth characterization of non-exhaust traffic emissions from the Munich subway system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 915:170008. [PMID: 38220016 DOI: 10.1016/j.scitotenv.2024.170008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 12/27/2023] [Accepted: 01/06/2024] [Indexed: 01/16/2024]
Abstract
A SEM/EDX based automated measurement and classification algorithm was tested as a method for the in-depth analysis of micro-environments in the Munich subway using a custom build mobile measurements system. Sampling was conducted at platform stations, to investigate the personal exposure of commuters to subway particulate matter during platform stays. EDX spectra and morphological features of all analyzed particles were automatically obtained and particles were automatically classified based on pre-defined chemical and morphological boundaries. Source apportionment for individual particles, such as abrasion processes at the wheel-brake interface, was partially possible based on the established particle classes. An average of 98.87 ± 1.06 % of over 200,000 analyzed particles were automatically assigned to the pre-defined classes, with 84.68 ± 16.45 % of particles classified as highly ferruginous. Manual EDX analysis further revealed, that heavy metal rich particles were also present in the ultrafine size range well below 100 nm.
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Affiliation(s)
- Carsten Neukirchen
- University of the Bundeswehr Munich, Faculty for Mechanical Engineering, Institute of Chemical and Environmental Engineering, Werner-Heisenberg-Weg 39, 85577 Neubiberg, Germany; Joint Mass Spectrometry Center (JMSC) at Chair of Analytical Chemistry, Institute of Chemistry, University of Rostock, Albert-Einstein-Strasse 27, 18059 Rostock, Germany
| | - Thorsten Meiners
- Oxford Instruments GmbH, Borsigstraße 15 A, 652025 Wiesbaden, Germany
| | - Jan Bendl
- University of the Bundeswehr Munich, Faculty for Mechanical Engineering, Institute of Chemical and Environmental Engineering, Werner-Heisenberg-Weg 39, 85577 Neubiberg, Germany; Institute for Environmental Studies, Faculty of Science, Charles University, Benátská 2, 128 01 Prague, Czech Republic.
| | - Ralf Zimmermann
- Joint Mass Spectrometry Center (JMSC) at Comprehensive Molecular Analytics (CMA), Department Environmental Health, Helmholtz Munich, Gmunder Str. 37, 81379 München, Germany; Joint Mass Spectrometry Center (JMSC) at Chair of Analytical Chemistry, Institute of Chemistry, University of Rostock, Albert-Einstein-Strasse 27, 18059 Rostock, Germany
| | - Thomas Adam
- University of the Bundeswehr Munich, Faculty for Mechanical Engineering, Institute of Chemical and Environmental Engineering, Werner-Heisenberg-Weg 39, 85577 Neubiberg, Germany; Joint Mass Spectrometry Center (JMSC) at Comprehensive Molecular Analytics (CMA), Department Environmental Health, Helmholtz Munich, Gmunder Str. 37, 81379 München, Germany
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