Seasonal Influence of Road Proximity and Classroom Type on School Respirable Dust Levels in Chiang Rai Province, Thailand

Seasonal Influence of Road Proximity and Classroom Type on School Respirable Dust Levels in Chiang Rai Province, Thailand | 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 Seasonal Influence of Road Proximity and Classroom Type on School Respirable Dust Levels in Chiang Rai Province, Thailand Weerapong Thanjangreed, Anchalee Katramee, Saharat Arreras This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8599382/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 4 You are reading this latest preprint version Abstract This study aims to investigate respirable dust concentrations using personal air samplers with PVC filters at six schools, both proximal and distal to roadways, during dry and wet seasons in Chiang Rai Province, Thailand. Indoor/Outdoor ratios (I/O ratios) were calculated using respirable dust samples in both indoor and outdoor classrooms of schools situated both near and far from roadways to evaluate particle infiltration. Seasonal effects on respirable dust concentrations were examined using meteorological parameters. Respirable dust concentrations during the dry season were substantially higher (80.50±0.94–127.40±1.25 µg/m3) than during the wet season (16.68±0.60–25.98±1.51 µg/m3), highlighting the influence of biomass combustion, dust resuspension, and the absence of precipitation. Schools located near major roadways showed higher concentrations than those farther away, particularly in the wet season (p < 0.05). During the dry season, indoor/outdoor ratios approached unity (0.96–1.00), indicating nearly complete infiltration. I/O ratios varied from 0.86 to 1.00 during the wet season, with nearly covered classrooms providing some protection. This study found that students and educators in northern Thailand are exposed to elevated levels of respirable dust throughout the year. Biomass burning is the primary source in the dry season, while traffic-related emissions and classroom design play a larger role in the wet season. These findings highlight the need for integrated policies that combine regional biomass combustion reduction strategies with localized interventions, such as improved classroom enclosures and air purification systems, to better protect vulnerable schoolchildren. Respirable particulate matter Indoor air quality School environment exposure Seasonal air pollution Traffic-related emissions and Northern Thailand Full Text Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 10 Mar, 2026 Reviewers invited by journal 22 Jan, 2026 Editor assigned by journal 19 Jan, 2026 First submitted to journal 15 Jan, 2026 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-8599382","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":578741512,"identity":"5bf5722a-f747-4c15-a7a8-1090e542c104","order_by":0,"name":"Weerapong Thanjangreed","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA+UlEQVRIiWNgGAWjYJADNgaGCgZ+KOcAMTqYgVrOMEg2gDkJxGphbCNCi8Hx5mMffu6wyZN34D/24Oe8bRIGB5gffmD8cQe3ljPHkmf2nkkrNjzAzG7Yu+02UAubsQRDwjOcWsxu5Bgz8LYdTtzYwMwmwbvtdp3BAQYzoMMO49Zy//1nxr9QLZJ/54BsYf+GX8sNHmZmkC3zgd6X5m0AaeHBb4v9mTRjZtkzaYkbmJnNpGWO3ZaQPMxTLJGQhluLZPvhx4xvd9gkzm9vfCb5pua2BN/x9o0fPtjg1gIGjA3AoIOrYQbiBPwaIFrkGwipGgWjYBSMghELALnFV090//DhAAAAAElFTkSuQmCC","orcid":"https://orcid.org/0009-0000-1353-814X","institution":"Mae Fah Luang University","correspondingAuthor":true,"prefix":"","firstName":"Weerapong","middleName":"","lastName":"Thanjangreed","suffix":""},{"id":578741513,"identity":"3efe8ae6-ec24-41d4-9883-5f97991b8e49","order_by":1,"name":"Anchalee Katramee","email":"","orcid":"","institution":"Mae Fah Luang University","correspondingAuthor":false,"prefix":"","firstName":"Anchalee","middleName":"","lastName":"Katramee","suffix":""},{"id":578741514,"identity":"82e3949e-5980-41d1-9e5e-d1f8924366cb","order_by":2,"name":"Saharat Arreras","email":"","orcid":"","institution":"Mae Fah Luang University","correspondingAuthor":false,"prefix":"","firstName":"Saharat","middleName":"","lastName":"Arreras","suffix":""}],"badges":[],"createdAt":"2026-01-14 08:29:47","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8599382/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8599382/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":101212896,"identity":"b72dd56c-9c44-44da-8d2e-3e0c71c9dd8f","added_by":"auto","created_at":"2026-01-27 10:29:08","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1113565,"visible":true,"origin":"","legend":"","description":"","filename":"Manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8599382/v1_covered_7c6575dd-ed82-44cd-8351-476dba1511cb.pdf"}],"financialInterests":"","formattedTitle":"Seasonal Influence of Road Proximity and Classroom Type on School Respirable Dust Levels in Chiang Rai Province, Thailand","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"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":"environmental-science-and-pollution-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"espr","sideBox":"Learn more about [Environmental Science and Pollution Research](https://www.springer.com/journal/11356)","snPcode":"11356","submissionUrl":"https://submission.nature.com/new-submission/11356/3","title":"Environmental Science and Pollution Research","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Respirable particulate matter, Indoor air quality, School environment exposure, Seasonal air pollution, Traffic-related emissions, and Northern Thailand","lastPublishedDoi":"10.21203/rs.3.rs-8599382/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8599382/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"This study aims to investigate respirable dust concentrations using personal air samplers with PVC filters at six schools, both proximal and distal to roadways, during dry and wet seasons in Chiang Rai Province, Thailand. Indoor/Outdoor ratios (I/O ratios) were calculated using respirable dust samples in both indoor and outdoor classrooms of schools situated both near and far from roadways to evaluate particle infiltration. Seasonal effects on respirable dust concentrations were examined using meteorological parameters. Respirable dust concentrations during the dry season were substantially higher (80.50±0.94–127.40±1.25 µg/m3) than during the wet season (16.68±0.60–25.98±1.51 µg/m3), highlighting the influence of biomass combustion, dust resuspension, and the absence of precipitation. Schools located near major roadways showed higher concentrations than those farther away, particularly in the wet season (p \u0026lt; 0.05). During the dry season, indoor/outdoor ratios approached unity (0.96–1.00), indicating nearly complete infiltration. I/O ratios varied from 0.86 to 1.00 during the wet season, with nearly covered classrooms providing some protection. This study found that students and educators in northern Thailand are exposed to elevated levels of respirable dust throughout the year. Biomass burning is the primary source in the dry season, while traffic-related emissions and classroom design play a larger role in the wet season. 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