{"title":"Cost-effective indoor air quality monitoring in schools: in-field calibration of PM low-cost sensor","authors":"J.P. Sá, H. Chojer, P.T.B.S. Branco, M.C.M. Alvim-Ferraz, F.G. Martins, S.I.V. Sousa","doi":"10.1016/j.dibe.2025.100762","DOIUrl":null,"url":null,"abstract":"<div><div>The availability of low-cost sensors (LCS) devices for indoor air monitoring has boosted air pollution field. This study aims to calibrate particulate matter (PM) LCS (PM<sub>1</sub>, PM<sub>2.5</sub> and PM<sub>10</sub>) in four age groups/types of rooms (infants, preschoolers, schoolers and lunchroom) during occupancy and non-occupancy period in nursery and primary schools in Porto, considering the purpose of being used as a tool to empower schools to apply indoor air pollution (IAP) mitigation measures.</div><div>Sixteen LCS devices (AirVisual Pro) and three research-grade instruments (DustTrak DRX 8534/8533) were used to monitor PM in around 130 different samplings. Before calibration, a methodology approach based on local maxima was applied to all PM fractions of LCS data, since various error events were found. Thus, after identifying and removing these events, a merged dataset was created using 1-min mean of LCS and reference data. Calibration models were applied, such as simple and multiple linear regressions (LR and MLR), linear and non-linear support vector regression (SVR) and gradient boosting regression (GBR).</div><div>A strong linear relationship was observed between LCS device and reference data, especially for non-occupancy period and in finer PM fractions (Pearson's correlation reached 0.94 for PM<sub>1</sub> and PM<sub>2.5</sub>). While PM<sub>10</sub> exhibited a slightly weaker correlation than the other PM fractions. The calibration models, particularly SVR and GBR models, significantly improved the results depending on the PM fraction, age group/type of room and occupancy pattern. Overall, results indicated that LCS devices are an effective tool for managing IAQ in schools, based on PM sensor.</div></div>","PeriodicalId":34137,"journal":{"name":"Developments in the Built Environment","volume":"24 ","pages":"Article 100762"},"PeriodicalIF":8.2000,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Developments in the Built Environment","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2666165925001620","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CONSTRUCTION & BUILDING TECHNOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
The availability of low-cost sensors (LCS) devices for indoor air monitoring has boosted air pollution field. This study aims to calibrate particulate matter (PM) LCS (PM1, PM2.5 and PM10) in four age groups/types of rooms (infants, preschoolers, schoolers and lunchroom) during occupancy and non-occupancy period in nursery and primary schools in Porto, considering the purpose of being used as a tool to empower schools to apply indoor air pollution (IAP) mitigation measures.
Sixteen LCS devices (AirVisual Pro) and three research-grade instruments (DustTrak DRX 8534/8533) were used to monitor PM in around 130 different samplings. Before calibration, a methodology approach based on local maxima was applied to all PM fractions of LCS data, since various error events were found. Thus, after identifying and removing these events, a merged dataset was created using 1-min mean of LCS and reference data. Calibration models were applied, such as simple and multiple linear regressions (LR and MLR), linear and non-linear support vector regression (SVR) and gradient boosting regression (GBR).
A strong linear relationship was observed between LCS device and reference data, especially for non-occupancy period and in finer PM fractions (Pearson's correlation reached 0.94 for PM1 and PM2.5). While PM10 exhibited a slightly weaker correlation than the other PM fractions. The calibration models, particularly SVR and GBR models, significantly improved the results depending on the PM fraction, age group/type of room and occupancy pattern. Overall, results indicated that LCS devices are an effective tool for managing IAQ in schools, based on PM sensor.
期刊介绍:
Developments in the Built Environment (DIBE) is a recently established peer-reviewed gold open access journal, ensuring that all accepted articles are permanently and freely accessible. Focused on civil engineering and the built environment, DIBE publishes original papers and short communications. Encompassing topics such as construction materials and building sustainability, the journal adopts a holistic approach with the aim of benefiting the community.