Mid-term calibration and performance of low-cost multi-sensor systems for urban air quality monitoring

Mid-term calibration and performance of low-cost multi-sensor systems for urban air quality monitoring | 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 Mid-term calibration and performance of low-cost multi-sensor systems for urban air quality monitoring Sofia Fellini, Davide Gallione, Vincenzo Vaccaro, Nicole Mastromatteo, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7178992/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 10 You are reading this latest preprint version Abstract This study evaluates a mid-term calibration strategy for MONICA, a compact low-cost multi-sensor system designed for urban air quality monitoring. The goal is to optimize the trade-off between calibration duration and monitoring performance, addressing the operational constraints of real-world deployments. A three-and-a-half-month co-location campaign was conducted with reference-grade instruments to calibrate and assess MONICA's performance for PM \((_{2.5})\) , PM \((_{10})\) , and NO \((_{2})\) using three models: Multiple Linear Regression (MLR), Random Forest (RF), and Generalized Additive Models (GAM).MLR showed the most stable performance across the entire monitoring period, while RF and GAM provided high short-term accuracy but exhibited reduced robustness outside the calibration window. A two-week calibration period was sufficient for PM sensors, while one week sufficed for NO \((_2)\) . Despite gradual performance degradation—especially for NO \((_2)\) —MONICA successfully captured pollutant trends and regulatory exceedances defined by EU Directive 2024/2881. The results provide practical guidance for implementing scalable LCS networks in time-limited urban monitoring campaigns. Low-cost sensors Air quality monitoring Sensor calibration Urban environment Calibration-deployment trade-off EU Directive 2024/2881 Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 06 Feb, 2026 Reviews received at journal 03 Feb, 2026 Reviewers agreed at journal 13 Jan, 2026 Reviews received at journal 15 Dec, 2025 Reviewers agreed at journal 18 Nov, 2025 Reviewers agreed at journal 10 Nov, 2025 Reviewers invited by journal 03 Aug, 2025 Editor assigned by journal 30 Jul, 2025 Submission checks completed at journal 27 Jul, 2025 First submitted to journal 25 Jul, 2025 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. 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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-7178992","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":494855083,"identity":"234819ac-9845-4fca-8117-b78eba779ad5","order_by":0,"name":"Sofia 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Calibration-deployment trade-off, EU Directive 2024/2881","lastPublishedDoi":"10.21203/rs.3.rs-7178992/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7178992/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study evaluates a mid-term calibration strategy for MONICA, a compact low-cost multi-sensor system designed for urban air quality monitoring. The goal is to optimize the trade-off between calibration duration and monitoring performance, addressing the operational constraints of real-world deployments. A three-and-a-half-month co-location campaign was conducted with reference-grade instruments to calibrate and assess MONICA's performance for PM\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\((_{2.5})\\)\u003c/span\u003e\u003c/span\u003e, PM\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\((_{10})\\)\u003c/span\u003e\u003c/span\u003e, and NO\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\((_{2})\\)\u003c/span\u003e\u003c/span\u003e using three models: Multiple Linear Regression (MLR), Random Forest (RF), and Generalized Additive Models (GAM).MLR showed the most stable performance across the entire monitoring period, while RF and GAM provided high short-term accuracy but exhibited reduced robustness outside the calibration window. A two-week calibration period was sufficient for PM sensors, while one week sufficed for NO\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\((_2)\\)\u003c/span\u003e\u003c/span\u003e. Despite gradual performance degradation\u0026mdash;especially for NO\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\((_2)\\)\u003c/span\u003e\u003c/span\u003e\u0026mdash;MONICA successfully captured pollutant trends and regulatory exceedances defined by EU Directive 2024/2881. The results provide practical guidance for implementing scalable LCS networks in time-limited urban monitoring campaigns.\u003c/p\u003e","manuscriptTitle":"Mid-term calibration and performance of low-cost multi-sensor systems for urban air quality monitoring","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-05 09:17:45","doi":"10.21203/rs.3.rs-7178992/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-02-06T06:28:28+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-03T16:36:32+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"288928339286552316303410411989477277588","date":"2026-01-13T15:16:14+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-15T14:10:45+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"218563217549261215047399465523724577762","date":"2025-11-18T07:43:21+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"9742215738741976697421083479828607372","date":"2025-11-11T02:33:01+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-08-03T08:31:19+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-07-30T15:23:43+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-07-28T03:59:55+00:00","index":"","fulltext":""},{"type":"submitted","content":"Aerosol and Air Quality Research","date":"2025-07-25T07:04:11+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":false,"email":"","identity":"aerosol-and-air-quality-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"","title":"Aerosol and Air Quality Research","twitterHandle":"","acdcEnabled":false,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"VoR Journals","inReviewEnabled":false,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"f9c969a8-c019-4d6f-ac1a-6064842826ef","owner":[],"postedDate":"August 5th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-02T11:24:54+00:00","versionOfRecord":[],"versionCreatedAt":"2025-08-05 09:17:45","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7178992","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7178992","identity":"rs-7178992","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}