{"id":40,"date":"2026-10-16T19:38:30","date_gmt":"2026-10-16T19:38:30","guid":{"rendered":"https:\/\/ieqinsight.com\/?page_id=40"},"modified":"2026-10-16T19:38:30","modified_gmt":"2026-10-16T19:38:30","slug":"sleep-period-indoor-air-quality-in-hotel-guestrooms-apacchrie-2026","status":"publish","type":"page","link":"https:\/\/ieqinsight.com\/?page_id=40","title":{"rendered":"Sleep-Period Indoor Air Quality in Hotel Guestrooms \u2014 APacCHRIE 2026"},"content":{"rendered":"<style>\nbody:has(.ieq-publications){background:#f6f5f0}\nbody:has(.ieq-publications) main>.wp-block-group:has(.wp-block-post-title){display:none}\nbody:has(.ieq-publications) .wp-site-blocks{padding:0}\nbody:has(.ieq-publications) .wp-site-blocks>header,body:has(.ieq-publications) .wp-site-blocks>footer,body:has(.ieq-publications) .wp-block-post-title{display:none}\nbody:has(.ieq-publications) .wp-site-blocks>main,body:has(.ieq-publications) 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.pub-topic{display:inline;margin-left:16px}.ieq-publications .pub-hero{padding-top:40px;padding-bottom:40px}}<\/style><style>.ieq-publications .study-hero{background:linear-gradient(120deg,#edf9ff,#fff 65%,#effbf3);padding:55px 0;border-bottom:3px solid #20b6bd}.ieq-publications .study-hero h1{font-size:clamp(32px,4vw,52px);line-height:1.15;letter-spacing:-1.3px;max-width:1040px}.ieq-publications .study-authors{margin-top:24px;color:#405a73;font-size:16px}.ieq-publications .study-meta{margin-top:12px;font-size:14px;color:#087d37}.ieq-publications .study-body{max-width:1000px;padding-top:30px;padding-bottom:60px}.ieq-publications .study-body h2{font-size:30px;margin:36px 0 16px}.ieq-publications .study-body h3{font-size:23px;margin:25px 0 16px}.ieq-publications .study-body p{margin:15px 0;color:#405a73;font-size:16px;line-height:1.8}.ieq-publications .study-body p a{text-decoration:underline;overflow-wrap:anywhere;color:#0767b4}.ieq-publications figure{margin:30px 0;background:white;border:1px solid #d6e5ed;padding:15px;border-radius:5px}.ieq-publications figure img{width:100%;height:auto;display:block}.ieq-publications figcaption{font-size:13px;line-height:1.6;color:#405a73;margin-top:12px}.ieq-publications .table-scroll{overflow:auto}.ieq-publications table{border-collapse:collapse;width:100%;font-size:14px;color:#405a73;min-width:650px}.ieq-publications th,.ieq-publications td{padding:14px 12px;text-align:left;border-bottom:1px solid #d6e5ed}.ieq-publications thead{background:#edf8ff;color:#082653}.ieq-publications .study-body .figure-note{font-size:13px}.ieq-publications .back-link{display:inline-block;font-size:13px;color:#0767b4;margin-bottom:25px}<\/style><div class=\"ieq-publications\"><header class=\"wrap nav\"><a class=\"brand-logo\" href=\"https:\/\/ieqinsight.com\/\" aria-label=\"IEQ InSight Consulting home\"><img decoding=\"async\" src=\"https:\/\/ieqinsight.com\/wp-content\/uploads\/2026\/09\/ChatGPT-Image-Sep-22-2026-01_06_40-AM.png\" alt=\"IEQ InSight Consulting \u2014 Turning the invisible into actionable insight.\"><\/a><nav class=\"links\" aria-label=\"Main navigation\"><a href=\"https:\/\/ieqinsight.com\/\">Home<\/a><a href=\"https:\/\/ieqinsight.com\/#consulting\">Consulting<\/a><a href=\"https:\/\/ieqinsight.com\/?page_id=35\" aria-current=\"page\">Research<\/a><a href=\"https:\/\/ieqinsight.com\/#contact\">Connect \u2197<\/a><\/nav><\/header><section class=\"study-hero\"><div class=\"wrap\"><a class=\"back-link\" href=\"https:\/\/ieqinsight.com\/?page_id=35\">\u2190 All research &amp; publications<\/a><p class=\"eyebrow\">2026 \u00b7 Conference presentation \u00b7 Extended abstract<\/p><h1>Making the Invisible Visible: Sleep-Period Indoor Air Quality in Guestrooms of a Five-Star Conference Hotel<\/h1><p class=\"study-authors\">Howook \u201cSean\u201d Chang, DBA  \u00b7  Wonseok Seo, PhD  \u00b7  Changsup Shim, PhD  \u00b7  Adolfis Pimentel, MS<\/p><p class=\"study-meta\">APacCHRIE 2026  |  OSAKA, JAPAN  |  MAY 28\u201331, 2026<\/p><p class=\"study-meta\">Accepted and presented as a stand-up presentation at the 24th APacCHRIE Conference<\/p><nav class=\"topic-nav\" aria-label=\"Study sections\"><a href=\"#abstract\">Read extended abstract<\/a><a href=\"#charts\">View research charts<\/a><\/nav><\/div><\/section><article class=\"wrap study-body\" id=\"abstract\"><h2>Background and objective<\/h2><p>Restorative sleep is central to the hotel experience, yet hospitality management research often emphasizes perceptible attributes\u2014bedding, noise, lighting, and thermal comfort\u2014rather than the invisible air guests breathe overnight, which has been shown to influence sleep quality (Mao et al., 2018; Robbins et al., 2021). Among indoor air quality parameters, bedroom carbon dioxide (CO\u2082) serves as an indicator of outdoor-air ventilation and the accumulation of occupants\u2019 exhaled breath, and elevated concentrations have been associated with poorer sleep quality. For example, empirical research reported an estimated 4.3% reduction in deep-sleep percentage for every 100 ppm increase in overnight mean CO\u2082 concentration (Xiong et al., 2020). Based on a comprehensive review of bedroom ventilation and sleep research, Akimoto et al. (2025) recommend maintaining sleep-period CO\u2082 below 1,000 ppm and preferably at or below 800 ppm to minimize the risk of sleep disturbance. Similarly, Lin et al. (2026) associated greater bedroom PM\u2082.5 exposure with a smaller proportion of deep sleep and poorer next-day endurance performance. Motivated by this evidence, the present study investigated how objectively measured sleep-period indoor air quality (IAQ) varied across guestrooms and occupancy levels in a five-star hotel hosting a four-day international academic conference in Chiang Mai, Thailand.<\/p><h2>Field methods<\/h2><p>During the conference in May 2025, four occupied guestrooms with inoperable windows were monitored: two single-occupancy rooms (460 and 387 ft\u00b2), one double-occupancy room (387 ft\u00b2), and one triple-occupancy room (387 ft\u00b2). Two rooms were observed for four nights each and two for two nights each (12 room-nights). A bedside AirGradient ONE Cellular monitor recorded CO\u2082 (NDIR sensor), fine particulate matter (PM\u2082.\u2085; optical sensor), temperature, and relative humidity at three-minute intervals. From 5,476 total observations, 1,707 sleep-period records were identified using occupants\u2019 logged sleeping times. Analyses included room-level descriptive statistics, Kruskal\u2013Wallis tests on nightly summaries, Spearman correlations, and approximate CO\u2082-based ventilation estimates.<\/p><h2>Sleep-period results<\/h2><p>CO\u2082 accumulation, not PM\u2082.\u2085 pollution, was the principal difference among the rooms. The larger single-occupancy room (Corner Room) remained below the preferred 800 ppm benchmark throughout sleep, whereas the smaller single-occupancy room (Standard Room) exceeded it during 11.0% of sleep-period records. The double-occupancy room exceeded 800 ppm during 64.2% of records and the triple-occupancy room during all records. By contrast, sleep-period PM\u2082.\u2085 means were only 0.03\u20130.92 \u00b5g\/m\u00b3 across rooms.<\/p><h3>Table 1. Measured sleep-period indoor air quality<\/h3><div class=\"table-scroll\" tabindex=\"0\" role=\"region\" aria-label=\"Sleep-period indoor air quality results\"><table><thead><tr><th scope=\"col\">Guestroom \/ occupancy<\/th><th scope=\"col\">Mean CO\u2082 \u00b1 SD<br>(ppm)<\/th><th scope=\"col\">Peak CO\u2082<br>(ppm)<\/th><th scope=\"col\">CO\u2082 &gt; 800<br>(% records)<\/th><th scope=\"col\">Mean PM\u2082.\u2085<br>(\u00b5g\/m\u00b3)<\/th><\/tr><\/thead><tbody><tr><th scope=\"row\">Room 836 \u00b7 1 guest<br>460 ft\u00b2<\/th><td>644.63 \u00b1 53.79<\/td><td>772<\/td><td>0.0%<\/td><td>0.06<\/td><\/tr><tr><th scope=\"row\">Room 1018 \u00b7 1 guest<br>387 ft\u00b2<\/th><td>699.98 \u00b1 80.01<\/td><td>906<\/td><td>11.0%<\/td><td>0.92<\/td><\/tr><tr><th scope=\"row\">2 guests \u00b7 387 ft\u00b2<\/th><td>841.01 \u00b1 121.07<\/td><td>1,044<\/td><td>64.2%<\/td><td>0.03<\/td><\/tr><tr><th scope=\"row\">3 guests \u00b7 387 ft\u00b2<\/th><td>1,061.85 \u00b1 35.53<\/td><td>1,141<\/td><td>100.0%<\/td><td>0.04<\/td><\/tr><\/tbody><\/table><\/div><p>Note. Sleep-period n: Room 836 = 561; Room 1018 = 591; 2 guests = 299; 3 guests = 256. CO\u2082 is a ventilation proxy.<\/p><section id=\"charts\"><h2>CO\u2082 patterns across the stay<\/h2><p class=\"figure-note\">Shaded areas indicate sleeping periods. The orange line marks the study\u2019s preferred 800 ppm sleep-period reference, rather than a universal sleep-quality standard. These figures show CO\u2082 across the full monitoring period; the table summarizes sleep periods only.<\/p><figure><a href=\"https:\/\/ieqinsight.com\/wp-content\/uploads\/2026\/10\/image20261016-183215.png\" target=\"_blank\" rel=\"noopener\" aria-label=\"View single-occupancy chart at full size\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/ieqinsight.com\/wp-content\/uploads\/2026\/10\/image20261016-183215.png\" width=\"804\" height=\"441\" alt=\"CO\u2082 trends in single-occupancy rooms 836 and 1018 with shaded sleep periods and an 800 ppm reference line.\"><\/a><figcaption>Figure 1. Single-occupancy guestrooms: Room 836 and Room 1018. Select the chart to enlarge.<\/figcaption><\/figure><figure><a href=\"https:\/\/ieqinsight.com\/wp-content\/uploads\/2026\/10\/image20261016-183253.png\" target=\"_blank\" rel=\"noopener\" aria-label=\"View double- and triple-occupancy chart at full size\"><img decoding=\"async\" src=\"https:\/\/ieqinsight.com\/wp-content\/uploads\/2026\/10\/image20261016-183253.png\" width=\"812\" height=\"414\" alt=\"CO\u2082 trends in double- and triple-occupancy guestrooms with shaded sleep periods and an 800 ppm reference line.\" loading=\"lazy\"><\/a><figcaption>Figure 2. Double- and triple-occupancy guestrooms. Select the chart to enlarge.<\/figcaption><\/figure><\/section><h2>Statistical evidence and ventilation estimates<\/h2><p>Across 12 room-nights, nightly mean CO\u2082 differed among rooms (Kruskal\u2013Wallis H = 8.13, p = .043). Dunn\u2013Bonferroni testing identified a significant contrast between Room 836 and the triple-occupancy room (adjusted p = .049). The number of occupants correlated positively with both nightly mean and maximum CO\u2082 (Spearman \u03c1 = .794, p = .002 for each); correlations with PM\u2082.\u2085, temperature, and relative humidity were not significant. Because occupancy also differed by room, these observational associations cannot isolate occupancy effects from room-specific ventilation or configuration.<\/p><p>A steady-state CO\u2082 mass-balance approximation suggested fresh-air delivery of 19.76 L\/s\/person for single occupancy (averaged over the two single rooms), 11.88 L\/s\/person for double occupancy, and 7.79 L\/s\/person for triple occupancy. Estimates assumed outdoor CO\u2082 of 420 ppm and sleeping-adult CO\u2082 generation of 0.005 L\/s; they are not direct measurements of mechanical airflow. Average sleeping-period relative humidity ranged from 66.85% to 71.36%, above the optimal 40-60% reference. Brief daytime PM\u2082.\u2085 peaks may have coincided with housekeeping or room-entry activities, although sources were not verified.<\/p><h2>Implications for hospitality practice<\/h2><p>These findings illustrate a consequential distinction between clean air and fresh air: guestrooms may register negligible particulate pollution yet accumulate occupants\u2019 exhaled breath when outdoor-air ventilation is insufficient for the number of sleepers. Existing bedroom research associates higher CO\u2082, as a ventilation proxy, with less favorable sleep outcomes; the present study raises a concern about sleep-supportive conditions in shared rooms, but does not demonstrate impaired sleep among the participating guests.<\/p><p>Hotels should evaluate overnight ventilation under realistic single, double, and family occupancy, rather than assuming that performance for one guest extends to multiple occupants. Continuous CO\u2082 trends, combined with outdoor concentrations, occupancy data, and HVAC assessments, can inform ventilation adjustment, maintenance, and room-assignment decisions. Humid destinations also require attention to dehumidification alongside ventilation. By monitoring and responsibly communicating verified IAQ performance, hotel operators can make otherwise invisible infrastructure investments recognizable to guests and potentially differentiate their sleep and wellness offerings. Daytime particle spikes warrant additional assessment of housekeeping practices and staff exposures.<\/p><h2>Contribution and limitations<\/h2><p>By measuring air quality at the bedside during actual hotel stays, this case study extends perception-based hotel sleep research and demonstrates that sleep-period ventilation indicators can vary substantially within a single five-star property. Generalization is limited by four guestrooms in one hotel, only 12 room-nights, and indirect rather than measured outdoor-air supply. Neither objective nor self-reported sleep quality was assessed; observed CO\u2082 values must not be interpreted as proof of sleep impairment. Future multi-hotel research should combine overnight IAQ, measured airflow, occupancy, and validated sleep outcomes.<\/p><h2>Selected references<\/h2><p>Akimoto, M., et al. (2025). New research on bedroom ventilation and sleep quality suggests that building standards should be revisited. Science and Technology for the Built Environment, 31(8), 905\u2013916. <a href=\"https:\/\/doi.org\/10.1080\/23744731.2025.2531317\" target=\"_blank\" rel=\"noopener\">https:\/\/doi.org\/10.1080\/23744731.2025.2531317<\/a><\/p><p>Lin, X., et al. (2026). Association of bedroom particulate matter, sleep quality and next-day physical performance. Scientific Reports, 16, 7117. <a href=\"https:\/\/doi.org\/10.1038\/s41598-026-37949-2\" target=\"_blank\" rel=\"noopener\">https:\/\/doi.org\/10.1038\/s41598-026-37949-2<\/a><\/p><p>Mao, Z., Yang, Y., &amp; Wang, M. (2018). Sleepless nights in hotels? Understanding factors that influence hotel sleep quality. International Journal of Hospitality Management, 74, 189\u2013201. <a href=\"https:\/\/doi.org\/10.1016\/j.ijhm.2018.05.002\" target=\"_blank\" rel=\"noopener\">https:\/\/doi.org\/10.1016\/j.ijhm.2018.05.002<\/a><\/p><p>Robbins, R., Grandner, M., Knowlden, A., &amp; Severt, K. (2021). Examining key hotel attributes for guest sleep and overall satisfaction. Tourism and Hospitality Research, 21(2), 144\u2013155. <a href=\"https:\/\/doi.org\/10.1177\/1467358420961544\" target=\"_blank\" rel=\"noopener\">https:\/\/doi.org\/10.1177\/1467358420961544<\/a><\/p><p>Xiong, J., Lan, L., Lian, Z., &amp; de Dear, R. (2020). Associations of bedroom temperature and ventilation with sleep quality. Science and Technology for the Built Environment, 26(9), 1274\u20131284. <a href=\"https:\/\/doi.org\/10.1080\/23744731.2020.1756664\" target=\"_blank\" rel=\"noopener\">https:\/\/doi.org\/10.1080\/23744731.2020.1756664<\/a><\/p><\/article><footer class=\"wrap foot\"><span>\u00a9 2026 IEQ InSight<\/span><a href=\"https:\/\/ieqinsight.com\/?page_id=35\">Explore all research &amp; publications \u2192<\/a><\/footer><\/div>","protected":false},"excerpt":{"rendered":"<p>HomeConsultingResearchConnect \u2197 \u2190 All research &amp; publications 2026 \u00b7 Conference presentation \u00b7 Extended abstract Making the Invisible Visible: Sleep-Period Indoor Air Quality in Guestrooms of a Five-Star Conference Hotel Howook \u201cSean\u201d Chang, DBA \u00b7 Wonseok Seo, PhD \u00b7 Changsup Shim, PhD \u00b7 Adolfis Pimentel, MS APacCHRIE 2026 | OSAKA, JAPAN | MAY 28\u201331, 2026 Accepted [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-40","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/ieqinsight.com\/index.php?rest_route=\/wp\/v2\/pages\/40","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ieqinsight.com\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/ieqinsight.com\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/ieqinsight.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ieqinsight.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=40"}],"version-history":[{"count":1,"href":"https:\/\/ieqinsight.com\/index.php?rest_route=\/wp\/v2\/pages\/40\/revisions"}],"predecessor-version":[{"id":41,"href":"https:\/\/ieqinsight.com\/index.php?rest_route=\/wp\/v2\/pages\/40\/revisions\/41"}],"wp:attachment":[{"href":"https:\/\/ieqinsight.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=40"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}