Development of a Fast-Response Electrical Mobility Spectrometer for Ambient Ultrafine Particle Monitoring: Design and Numerical Optimization

Development of a Fast-Response Electrical Mobility Spectrometer for Ambient Ultrafine Particle Monitoring: Design and Numerical Optimization | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Development of a Fast-Response Electrical Mobility Spectrometer for Ambient Ultrafine Particle Monitoring: Design and Numerical Optimization Panich Intra This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8854833/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Accurate monitoring of ultrafine particles (UFPs) in ambient air is critical for environmental health assessment, yet it is often limited by the low time resolution and low charging efficiency of conventional bipolar scanning systems. This study presents the design and numerical optimization of a wide-range aerosol spectrometer (10–1000 nm) specifically engineered for high-temporal-resolution ambient monitoring. The instrument integrates a PM1.0 aerodynamic impactor, a high-intensity unipolar corona charger, and a fast-response electrometer. Unlike traditional designs, this system utilizes unipolar charging to achieve near-unity charging efficiency for accumulation mode particles, enabling a 1-minute scan time suitable for capturing dynamic environmental events. A comprehensive numerical model validating impactor aerodynamics, corona discharge physics, and transfer functions demonstrates that the system achieves a stable Townsend discharge with an N i t product exceeding 10 13 s.ions/m 3 . A Non-Negative Least Squares (NNLS) inversion algorithm was successfully implemented to recover size distributions with high fidelity. This optimized design provides a robust, cost-effective solution for expanding UFP monitoring capabilities in air quality networks. Ultrafine particles Electrical mobility spectrometer Unipolar charging Aerosol size distribution Environmental monitoring Numerical modeling Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8854833","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":600915155,"identity":"e1264d78-2241-4533-85eb-ab339fbf088e","order_by":0,"name":"Panich Intra","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA+ElEQVRIiWNgGAWjYJCCA4wNDDxg1gcQwQ4RTSCshY2BgXEGkMfDDBY0wKuFAaiFAaSFmYcYLebsZw8e+LmDQcZcvvfhZ9s92xL3MzMwfvjB8CcPlxbLnryEg71nGHgs29iNpXOe3U7sYWZgluxhMCjGpcXgQI7BYcY2Bh6DY2wM0jkHwFoYpIESiQ24tJx/A9fC/NsCooX5N14tNxC2sEkzQLSw4bXFcsYbg4O9bRJALWlslj0Hbhv3AE2w7DEwxqnFnD/H+MPPNht7g8PHmG/8OHBbtr29+fCNHxVyuB0GoSSQxUDRZIBDPQNeqVEwCkbBKBgFUAAABo9SjP18zhcAAAAASUVORK5CYII=","orcid":"","institution":"Rajamangala University of Technology Lanna","correspondingAuthor":true,"prefix":"","firstName":"Panich","middleName":"","lastName":"Intra","suffix":""}],"badges":[],"createdAt":"2026-02-11 18:24:28","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8854833/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8854833/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":106727661,"identity":"3f5198f1-66cd-4026-962e-e1cbada5b986","added_by":"auto","created_at":"2026-04-12 18:40:02","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":945280,"visible":true,"origin":"","legend":"","description":"","filename":"MSDMAIntra20261.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8854833/v1_covered_c4a238ef-f331-485f-8bfd-a77b707bb0aa.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Development of a Fast-Response Electrical Mobility Spectrometer for Ambient Ultrafine Particle Monitoring: Design and Numerical Optimization","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Ultrafine particles, Electrical mobility spectrometer, Unipolar charging, Aerosol size distribution, Environmental monitoring, Numerical modeling","lastPublishedDoi":"10.21203/rs.3.rs-8854833/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8854833/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eAccurate monitoring of ultrafine particles (UFPs) in ambient air is critical for environmental health assessment, yet it is often limited by the low time resolution and low charging efficiency of conventional bipolar scanning systems. This study presents the design and numerical optimization of a wide-range aerosol spectrometer (10\u0026ndash;1000 nm) specifically engineered for high-temporal-resolution ambient monitoring. The instrument integrates a PM1.0 aerodynamic impactor, a high-intensity unipolar corona charger, and a fast-response electrometer. Unlike traditional designs, this system utilizes unipolar charging to achieve near-unity charging efficiency for accumulation mode particles, enabling a 1-minute scan time suitable for capturing dynamic environmental events. A comprehensive numerical model validating impactor aerodynamics, corona discharge physics, and transfer functions demonstrates that the system achieves a stable Townsend discharge with an \u003cem\u003eN\u003c/em\u003e\u003csub\u003e\u003cem\u003ei\u003c/em\u003e\u003c/sub\u003e\u003cem\u003et\u003c/em\u003e product exceeding 10\u003csup\u003e13\u003c/sup\u003e s.ions/m\u003csup\u003e3\u003c/sup\u003e. 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