{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,8]],"date-time":"2026-05-08T11:09:54Z","timestamp":1778238594881,"version":"3.51.4"},"reference-count":57,"publisher":"SAGE Publications","issue":"6","license":[{"start":{"date-parts":[[2025,10,17]],"date-time":"2025-10-17T00:00:00Z","timestamp":1760659200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"},{"start":{"date-parts":[[2025,10,17]],"date-time":"2025-10-17T00:00:00Z","timestamp":1760659200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"funder":[{"DOI":"10.13039\/501100000038","name":"Natural Sciences and Engineering Research Council of Canada","doi-asserted-by":"publisher","award":["RGPIN 2022-03821"],"award-info":[{"award-number":["RGPIN 2022-03821"]}],"id":[{"id":"10.13039\/501100000038","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["Journal of Building Physics"],"published-print":{"date-parts":[[2026,5]]},"abstract":"<jats:p>\n                    Low-cost indoor air quality (IAQ) sensors offer new opportunities for real-time monitoring in the built environment by occupants and researchers. However, their performance can vary substantially depending on the environmental conditions. This study presents a comprehensive evaluation of carbon dioxide (CO\n                    <jats:sub>2<\/jats:sub>\n                    ) and fine particulate matter (PM\n                    <jats:sub>2.5<\/jats:sub>\n                    ) measurements from two consumer-grade low-cost sensors (the Airthings View Plus for CO\n                    <jats:sub>2<\/jats:sub>\n                    only and Air Gradient Pro for CO\n                    <jats:sub>2<\/jats:sub>\n                    and PM\n                    <jats:sub>2.5<\/jats:sub>\n                    ) through co-location tests with two reference instruments, Graywolf DSII-8 for CO\n                    <jats:sub>2<\/jats:sub>\n                    and Lighthouse Handheld 3016 for PM\n                    <jats:sub>2.5<\/jats:sub>\n                    . Using time-series analysis, linear regression, Pearson correlation, Root-Mean Squared Error (RMSE), Bland-Altman test, and paired\n                    <jats:italic toggle=\"yes\">t<\/jats:italic>\n                    -tests, we assess the precision and accuracy of these sensors. At a 5-minute sampling interval, the Air Gradient sensor had a higher coefficient of determination (\n                    <jats:italic toggle=\"yes\">R<\/jats:italic>\n                    <jats:sup>2<\/jats:sup>\n                    ), stronger Pearson correlation, and narrower range of limits of agreement (LoAs), but higher bias (i.e. the mean difference) and RMSE, suggesting higher precision but lower accuracy when compared to Airthings. As a result, it can perform well for tracking the relative changes in CO\n                    <jats:sub>2<\/jats:sub>\n                    , though less ideal for absolute concentrations without calibration. For PM\n                    <jats:sub>2.5<\/jats:sub>\n                    , the Air Gradient also had relatively high\n                    <jats:italic toggle=\"yes\">R<\/jats:italic>\n                    <jats:sup>2<\/jats:sup>\n                    (0.79), moderately strong Pearson correlation (\u03c1\u2009=\u20090.69,\n                    <jats:italic toggle=\"yes\">p<\/jats:italic>\n                    \u2009&lt;\u20090.05), and a narrow range of LOAs (30.1\u2009\u03bcg\/m\n                    <jats:sup>3<\/jats:sup>\n                    ) and low RMSE (5.8\u2009\u03bcg\/m\n                    <jats:sup>3<\/jats:sup>\n                    ). Averaging the 5-minute measurements over 30-minute intervals generally improved the accuracy and precision of both sensors. However, statistically significant differences from the reference instruments remained for both sensors. Overall, this study offers a multi-metric assessment of consumer-grade sensors and highlights the need for in-situ calibration prior to long-term deployment.\n                  <\/jats:p>","DOI":"10.1177\/17442591251367436","type":"journal-article","created":{"date-parts":[[2025,10,17]],"date-time":"2025-10-17T09:10:44Z","timestamp":1760692244000},"page":"829-851","update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":1,"title":["Validating the performance of low-cost IAQ sensors through co-location"],"prefix":"10.1177","volume":"49","author":[{"given":"Noor","family":"Zaky","sequence":"first","affiliation":[{"name":"Toronto Metropolitan University, ON, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tianyuan","family":"Li","sequence":"additional","affiliation":[{"name":"University of Waterloo, ON, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0680-7118","authenticated-orcid":false,"given":"Helen","family":"Stopps","sequence":"additional","affiliation":[{"name":"Toronto Metropolitan University, ON, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"179","published-online":{"date-parts":[[2025,10,17]]},"reference":[{"key":"e_1_3_2_2_1","doi-asserted-by":"publisher","DOI":"10.1039\/D2EA00149G"},{"key":"e_1_3_2_3_1","unstructured":"Air Gradient (n.d.) Indoor Air Quality Monitor. Available at: https:\/\/www.airgradient.com\/indoor\/ (accessed 22 November 2024)."},{"key":"e_1_3_2_4_1","unstructured":"Airthings (2024) Airthings delivered strong top-line growth in Q2 2024; Updates strategy. Available at: https:\/\/www.airthings.com\/newsroom\/q2_2024_press_release (accessed 22 November 2024)."},{"key":"e_1_3_2_5_1","volume-title":"Air Quality Monitor: View Plus","author":"Airthings","unstructured":"Airthings (n.d.) Air Quality Monitor: View Plus. Available at: https:\/\/www.airthings.com\/en-ca\/view-plus (accessed 22 November 2024)."},{"key":"e_1_3_2_6_1","volume-title":"ASHRAE 62.1 Ventilation and Acceptable Indoor Air Quality: Addendum ab","author":"ASHRAE","year":"2022","unstructured":"ASHRAE (2022) ASHRAE 62.1 Ventilation and Acceptable Indoor Air Quality: Addendum ab. Peachtree Corners, GA: ASHRAE."},{"key":"e_1_3_2_7_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.measen.2021.100059"},{"key":"e_1_3_2_8_1","doi-asserted-by":"publisher","DOI":"10.3390\/app122412940"},{"key":"e_1_3_2_9_1","doi-asserted-by":"publisher","DOI":"10.1111\/ina.12425"},{"key":"e_1_3_2_10_1","doi-asserted-by":"publisher","DOI":"10.1007\/s11869-020-00815-9"},{"key":"e_1_3_2_11_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jaerosci.2019.04.017"},{"key":"e_1_3_2_12_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.buildenv.2021.108014"},{"key":"e_1_3_2_13_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.envres.2018.01.024"},{"key":"e_1_3_2_14_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.buildenv.2020.107415"},{"key":"e_1_3_2_15_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.envres.2021.111560"},{"key":"e_1_3_2_16_1","doi-asserted-by":"publisher","DOI":"10.1021\/acs.est.4c02797"},{"key":"e_1_3_2_17_1","unstructured":"Durag Group (n.d.) MiniWRAS 1371 Portable wide-range aerosol spectrometer. Available at: https:\/\/www.durag.com\/en\/product-filter-837.htm?productID=MiniWRAS1371 (accessed 22 November 2024)."},{"key":"e_1_3_2_18_1","unstructured":"Evotech Air Quality (2023) Smart indoor air quality monitoring solutions. Available at: https:\/\/www.evotechairquality.co.uk\/assets\/files\/EvotechAirthingsBrochureOct23.pdf?static=1 (accessed 22 November 2024)."},{"key":"e_1_3_2_19_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.envpol.2018.10.064"},{"key":"e_1_3_2_20_1","unstructured":"Government of Canada (2021) Residential indoor air quality guidelines: Carbon dioxide. Available at: https:\/\/www.canada.ca\/en\/health-canada\/services\/publications\/healthy-living\/residential-indoor-air-quality-guidelines-carbon-dioxide.html (accessed 22 November 2024)."},{"key":"e_1_3_2_21_1","doi-asserted-by":"publisher","DOI":"10.1080\/02786826.2020.1851649"},{"issue":"3","key":"e_1_3_2_22_1","first-page":"520","article-title":"Low-cost PM2.5 sensors: An assessment of their suitability for various applications","volume":"20","author":"Jayaratne R","year":"2020","unstructured":"Jayaratne R, Liu X, Ahn KH, et al. (2020) Low-cost PM2.5 sensors: An assessment of their suitability for various applications. Aerosol and Air Quality Research 20(3): 520\u2013532.","journal-title":"Aerosol and Air Quality Research"},{"key":"e_1_3_2_23_1","doi-asserted-by":"publisher","DOI":"10.3390\/s20247290"},{"key":"e_1_3_2_24_1","doi-asserted-by":"publisher","DOI":"10.3390\/atmos10090506"},{"key":"e_1_3_2_25_1","doi-asserted-by":"publisher","DOI":"10.4209\/aaqr.230097"},{"issue":"5","key":"e_1_3_2_26_1","doi-asserted-by":"crossref","DOI":"10.1016\/j.heliyon.2022.e09354","article-title":"Assessment of indoor and outdoor air quality in primary schools of Cyprus during the COVID\u201319 pandemic measures in May\u2013","volume":"8","author":"Konstantinou C","year":"2022","unstructured":"Konstantinou C, Constantinou A, Kleovoulou EG, et al. (2022) Assessment of indoor and outdoor air quality in primary schools of Cyprus during the COVID\u201319 pandemic measures in May\u2013July 2021. Heliyon 8(5): e09354.","journal-title":"Heliyon"},{"key":"e_1_3_2_27_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.atmosenv.2016.05.052"},{"key":"e_1_3_2_28_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.buildenv.2017.11.001"},{"key":"e_1_3_2_29_1","doi-asserted-by":"publisher","DOI":"10.1111\/ina.12633"},{"key":"e_1_3_2_30_1","volume-title":"Lighthouse Handheld Technical Data Sheet","author":"Lighthouse Worldwide Solutions","unstructured":"Lighthouse Worldwide Solutions (n.d.) Lighthouse Handheld Technical Data Sheet. White City, Oregon: Lighthouse Worldwide Solutions."},{"key":"e_1_3_2_31_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.envres.2020.109438"},{"key":"e_1_3_2_32_1","doi-asserted-by":"publisher","DOI":"10.4209\/aaqr.2019.01.0045"},{"key":"e_1_3_2_33_1","volume-title":"Proceedings of the 2021 6th international symposium on environment-friendly energies and applications, EFEA 2021","author":"Marinov MB","year":"2021","unstructured":"Marinov MB, Ganev BT, Nikolov DN (2021) Indoor air quality assessment using low-cost commercial off-the-shelf sensors. In: Proceedings of the 2021 6th international symposium on environment-friendly energies and applications, EFEA 2021, Sofia, Bulgaria, 24\u201326 March 2021. New York, NY: IEEE."},{"key":"e_1_3_2_34_1","doi-asserted-by":"publisher","DOI":"10.5194\/jsss-7-373-2018"},{"key":"e_1_3_2_35_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.buildenv.2021.108237"},{"key":"e_1_3_2_36_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jobe.2023.107774"},{"key":"e_1_3_2_37_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.envpol.2024.124354"},{"key":"e_1_3_2_38_1","doi-asserted-by":"publisher","DOI":"10.1007\/s11356-022-22771-w"},{"key":"e_1_3_2_39_1","doi-asserted-by":"publisher","DOI":"10.1034\/j.1600-0668.2003.00189.x"},{"key":"e_1_3_2_40_1","doi-asserted-by":"publisher","DOI":"10.3390\/atmos13101579"},{"key":"e_1_3_2_41_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.scitotenv.2021.145304"},{"key":"e_1_3_2_42_1","doi-asserted-by":"publisher","DOI":"10.1111\/ina.12463"},{"key":"e_1_3_2_43_1","unstructured":"South Coast AQMD (n.d.) AQ-SPEC: Air quality sensor performance evaluation center. Available at: https:\/\/www.aqmd.gov\/aq-spec (accessed 22 November 2024)."},{"key":"e_1_3_2_44_1","doi-asserted-by":"publisher","DOI":"10.3233\/AIS-210458"},{"key":"e_1_3_2_45_1","first-page":"1010","volume-title":"Advances in Intelligent Systems and Computing","author":"Thomas D","year":"2019","unstructured":"Thomas D, Mistry B, Snow S, et al. (2019) Indoor air quality monitoring (IAQ): A low-cost alternative to CO2 monitoring in comparison to an industry standard device. In: Advances in Intelligent Systems and Computing. Cham: Springer Verlag, pp.1010\u20131027."},{"key":"e_1_3_2_46_1","doi-asserted-by":"publisher","DOI":"10.1155\/2018\/5353816"},{"key":"e_1_3_2_47_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.buildenv.2021.108398"},{"key":"e_1_3_2_48_1","unstructured":"United States Environmental Protection Agency (2024) Health and Environmental Effects of Particulate Matter (PM). Available at: https:\/\/www.epa.gov\/pm-pollution\/health-and-environmental-effects-particulate-matter-pm (accessed 22 November 2024)."},{"key":"e_1_3_2_49_1","unstructured":"United States Environmental Protection Agency (2025) Air sensor performance targets and testing protocols. Available at: https:\/\/www.epa.gov\/air-sensor-toolbox\/air-sensor-performance-targets-and-testing-protocols (accessed 7 July 2025)."},{"key":"e_1_3_2_50_1","doi-asserted-by":"publisher","DOI":"10.1021\/acssensors.0c01863"},{"key":"e_1_3_2_51_1","doi-asserted-by":"publisher","DOI":"10.1080\/09603123.2018.1533531"},{"key":"e_1_3_2_52_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.buildenv.2020.106654"},{"key":"e_1_3_2_53_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.atmosenv.2020.117615"},{"issue":"21","key":"e_1_3_2_54_1","first-page":"1","article-title":"A systematic review of air quality sensors, guidelines, and measurement studies for indoor air quality management","volume":"12","author":"Zhang H","year":"2020","unstructured":"Zhang H, Srinivasan R (2020) A systematic review of air quality sensors, guidelines, and measurement studies for indoor air quality management. Sustainability (Switzerland) 12(21): 1\u201340.","journal-title":"Sustainability (Switzerland)"},{"key":"e_1_3_2_55_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.aeolia.2022.100784"},{"key":"e_1_3_2_56_1","doi-asserted-by":"publisher","DOI":"10.1080\/23744731.2020.1778402"},{"key":"e_1_3_2_57_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.envint.2022.107372"},{"key":"e_1_3_2_58_1","doi-asserted-by":"publisher","DOI":"10.1111\/ina.12621"}],"container-title":["Journal of Building Physics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1177\/17442591251367436","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.sagepub.com\/doi\/full-xml\/10.1177\/17442591251367436","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1177\/17442591251367436","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,8]],"date-time":"2026-05-08T10:16:57Z","timestamp":1778235417000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.sagepub.com\/doi\/10.1177\/17442591251367436"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,10,17]]},"references-count":57,"journal-issue":{"issue":"6","published-print":{"date-parts":[[2026,5]]}},"alternative-id":["10.1177\/17442591251367436"],"URL":"https:\/\/doi.org\/10.1177\/17442591251367436","relation":{},"ISSN":["1744-2591","1744-2583"],"issn-type":[{"value":"1744-2591","type":"print"},{"value":"1744-2583","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,10,17]]}}}