Indoor EnvironmentsPub Date : 2026-03-01Epub Date: 2026-01-28DOI: 10.1016/j.indenv.2026.100155
Ayaka Kani , Ineko Tanaka
{"title":"Development of floor plan retrofit methods to reduce thermal health risks for low thermal performance houses in humid subtropical climate of Japan","authors":"Ayaka Kani , Ineko Tanaka","doi":"10.1016/j.indenv.2026.100155","DOIUrl":"10.1016/j.indenv.2026.100155","url":null,"abstract":"<div><div>According to the Japanese government, 90 % of the existing housing in Japan is poorly insulated and does not meet the current insulation standards. Poor thermal performance in housing affects the risk of heat-related illness among older adults in summer. In winter, it increases indoor temperature differences, thereby elevating the risk of bath-related acute cardiovascular events. Retrofitting is desirable to reduce thermal health risks in both seasons. However, insulation retrofits have not been widely implemented in Japan because of their high costs. Therefore, this study focuses on combining retrofitting to improve the thermal environment with floor plan modifications, which are generally implemented in response to life stage changes in Japan. In our previous work, we have proposed floor plan retrofit methods to reduce winter thermal health risk. However, summer health risks also need to be considered because elevated indoor temperatures have been associated with heat-related illness among older adults. This study aims to develop new retrofit methods for reducing thermal health risks in summer and winter through floor plan modifications. Numerical simulations using a generic detached-house model showed that, on the hottest day, the toilet room temperature in the proposed model was 4 K lower than in the original model. Furthermore, when additional measures to reduce west-facing solar heat gains were incorporated into the winter-optimised floor plan, thermal health risks in both seasons decreased compared with the original model. These results indicate that the proposed retrofit methods are effective in reducing thermal health risks.</div></div>","PeriodicalId":100665,"journal":{"name":"Indoor Environments","volume":"3 1","pages":"Article 100155"},"PeriodicalIF":0.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146188832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Indoor EnvironmentsPub Date : 2026-03-01Epub Date: 2025-12-16DOI: 10.1016/j.indenv.2025.100146
Alice E.E. Handy, Samuel G.A. Wood, Henry C. Burridge, SAMHE Project Consortium
{"title":"Analysing longitudinal indoor air quality data: robust principal component analysis of the “Schools’ Air quality Monitoring for Health and Education” timeseries data","authors":"Alice E.E. Handy, Samuel G.A. Wood, Henry C. Burridge, SAMHE Project Consortium","doi":"10.1016/j.indenv.2025.100146","DOIUrl":"10.1016/j.indenv.2025.100146","url":null,"abstract":"<div><div>A robust principal component analysis examining two-years of monitored data from within 143 UK schools as part of the “Schools’ Air quality Monitoring for Health and Education” dataset sheds new light on the temporal and geographical trends that influence the schools’ air quality. Minutely concentration measurements of two indoor air quality markers, particulate matter and carbon dioxide, were analysed. Significant inter-school variations were evident in both species but the primary source of variations within the particulate matter concentrations were temporal trends. Analysis links these temporal trends to variations in outdoor particulate matter concentrations — highlighting the importance of outdoor air quality for the air quality in UK schools. Moreover, clear geographical signatures are identified within the particulate matter concentrations in schools, broadly increasing both South–North and East–West; with more subtle but intelligible trends overlaid within each. Analysis of the carbon dioxide data identifies variations on a range of time scales from seasonal trends, associated with the changing levels of ventilation as UK schools open their windows less in cooler wintertime conditions, down to inter-day variations as carbon dioxide levels increase during the school morning. This study provides the first evidence as to the insights that can be gained when large-scale longitudinal monitoring of indoor spaces, in this case schools, is carried out. The insights that were determined from analysis of two-years of data from the SAMHE schools could not have been realised by analysis of smaller datasets.</div></div>","PeriodicalId":100665,"journal":{"name":"Indoor Environments","volume":"3 1","pages":"Article 100146"},"PeriodicalIF":0.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Indoor EnvironmentsPub Date : 2026-03-01Epub Date: 2026-02-13DOI: 10.1016/j.indenv.2026.100159
Lars Andrup
{"title":"Common respiratory infections in the workplace: An often-neglected occupational health priority","authors":"Lars Andrup","doi":"10.1016/j.indenv.2026.100159","DOIUrl":"10.1016/j.indenv.2026.100159","url":null,"abstract":"","PeriodicalId":100665,"journal":{"name":"Indoor Environments","volume":"3 1","pages":"Article 100159"},"PeriodicalIF":0.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147397160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Indoor EnvironmentsPub Date : 2026-03-01Epub Date: 2026-01-29DOI: 10.1016/j.indenv.2026.100154
Anna Conzatti , Noorullah Kuchai , Elif Keser , Dima Albadra , Daniel Fosas , David Coley
{"title":"Co-creation of an airflow and COVID-19 transmission risk model for humanitarian shelter design","authors":"Anna Conzatti , Noorullah Kuchai , Elif Keser , Dima Albadra , Daniel Fosas , David Coley","doi":"10.1016/j.indenv.2026.100154","DOIUrl":"10.1016/j.indenv.2026.100154","url":null,"abstract":"<div><div>Ventilation rates in overcrowded humanitarian shelters are often insufficient to prevent condensation, respiratory illness, and the transmission of airborne diseases. Enhancing ventilation is challenging due to security needs, protection from dust and insects, and a lack of design expertise among humanitarian teams without engineering backgrounds. This study presents the development, validation, and testing of a novel natural-ventilation and infection-risk assessment methodology co-designed with 42 practitioners from NGOs, humanitarian organisations, and academia through a six-phase participatory process. The new methodology requires approximately 20 inputs to characterise shelter conditions across more than 3100 global locations and performs natural-ventilation, indoor CO₂, and COVID-19 transmission-risk calculations without the need for prior airflow-modelling knowledge. Model performance was evaluated against established network models (EnergyPlus Airflow Network and CONTAM) using representative shelters in Ethiopia, Djibouti, and Nepal, demonstrating good agreement. Usability testing with 12 aid workers showed that first-time users could complete a full shelter assessment in about 30 min, with subsequent iterations requiring around 15 min. The method provides a rapid, accessible method for estimating ventilation adequacy and airborne-diseases risk in resource-constrained settings and has been adopted by several humanitarian agencies to support emergency shelter design and ventilation decision-making.</div></div>","PeriodicalId":100665,"journal":{"name":"Indoor Environments","volume":"3 1","pages":"Article 100154"},"PeriodicalIF":0.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146188813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Indoor EnvironmentsPub Date : 2026-03-01Epub Date: 2026-02-12DOI: 10.1016/j.indenv.2026.100158
Youngbo Won, Wenhao Chen, Zhong-Min Wang, Jeff Wagner, Kazukiyo Kumagai
{"title":"Analysis of impact of ventilation and air cleaning strategies on classroom PM2.5 and CO2 under normal and wildfire conditions – A CONTAM simulation study","authors":"Youngbo Won, Wenhao Chen, Zhong-Min Wang, Jeff Wagner, Kazukiyo Kumagai","doi":"10.1016/j.indenv.2026.100158","DOIUrl":"10.1016/j.indenv.2026.100158","url":null,"abstract":"<div><div>Particulate matter (especially PM₂.₅) and carbon dioxide (CO₂) are key indicators of indoor air quality (IAQ). This study uses a multizone model (CONTAM) to simulate PM₂.₅ and CO₂ concentrations for representative ventilation scenarios with or without portable air cleaners (PACs) in a K-5 school during normal and wildfire conditions. The CONTAM model mimicked the measurement setup, consisting of one hallway and eight mechanically ventilated classrooms, each having approximately 20 students. After validating the model against measurement data, 50 more scenarios were simulated by changing ventilation conditions (mechanical vs. natural ventilation) and PAC operations under both normal conditions and wildfire conditions. Simulation results indicate that under normal conditions, HVAC system operating at 12 h<sup>−1</sup> with 20% outdoor air and a MERV 8 filter maintained average PM₂.₅ and CO₂ concentrations below 5 µg/m³ and 1000 ppm, respectively. Using a MERV 13 filter further reduced PM₂.₅ concentrations to 3 µg/m³ . During wildfire conditions, when outdoor PM₂.₅ reached 30 µg/m³ , indoor PM₂.₅ levels were over 10 µg/m³ for the same HVAC setup with a MERV 8 filter. Under the natural ventilation condition, indoor PM levels followed outdoor levels within 2 h without PACs. During wildfire, operating PACs is highly recommended. Opening a door facing outdoors with one window open quickly increase indoor PM₂.₅ and CO₂ concentrations by outdoor levels, while opening a door facing hallway did not. These findings highlight the importance of reducing outdoor air intake and utilizing effective filtration strategies to mitigate wildfire-related impacts on IAQ in schools.</div></div>","PeriodicalId":100665,"journal":{"name":"Indoor Environments","volume":"3 1","pages":"Article 100158"},"PeriodicalIF":0.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147397161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Association of indoor thermal environment with children’s physical activity in summer and winter","authors":"Aoi Hyakutake , Shun Kawakubo , Daisuke Umemoto , Keiko Sekiya , Hiroshi Nakagawa , Toshiharu Ikaga","doi":"10.1016/j.indenv.2025.100147","DOIUrl":"10.1016/j.indenv.2025.100147","url":null,"abstract":"<div><div>Indoor environments play an important role in children’s health and behavior, yet the impact of thermal environments on physical activity remains insufficiently understood. This study investigated the association between indoor thermal environments and children’s physical activity in summer and winter in Japan. Detailed indoor thermal measurements and objective accelerometer data were collected from 26 children aged 4–12 years, each measured in both seasons under parental supervision to ensure data quality. Significant associations were found between temperatures in living areas and physical activity intensity. Warmer indoor environments in winter were associated with higher activity intensity, whereas cooler indoor environments in summer were associated with lower activity intensity. A new indicator, the seasonal activity ratio (SAR), defined as the ratio of winter to summer activity intensity, was developed to assess the degree of seasonal variation. The SAR showed an overall seasonal decline (mean SAR: 0.96 ± 0.06). Children living in homes where non-living areas maintained cooler environments in summer and warmer environments in winter exhibited significantly smaller seasonal declines in activity compared with those in other environments. These findings demonstrate that even in modern, high-performance homes, a thermal design strategy is required that addresses both living and non-living areas in order to promote children’s physical activity year-round and to mitigate typical winter declines. The results of this study provide objective evidence to inform residential design and policies aimed at fostering healthier indoor environmental quality for children.</div></div>","PeriodicalId":100665,"journal":{"name":"Indoor Environments","volume":"3 1","pages":"Article 100147"},"PeriodicalIF":0.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Indoor EnvironmentsPub Date : 2026-03-01Epub Date: 2026-01-15DOI: 10.1016/j.indenv.2026.100150
Rachel Hurley , Oren Mangoubi , Shichao Liu
{"title":"Indoor wildfire smoke perceptions “nudge” mitigation behaviors","authors":"Rachel Hurley , Oren Mangoubi , Shichao Liu","doi":"10.1016/j.indenv.2026.100150","DOIUrl":"10.1016/j.indenv.2026.100150","url":null,"abstract":"<div><div>As wildfire smoke can travel long distances and affect more communities, understanding the link between smoke perception, health, and behavior is crucial for reducing smoke exposure. This study examines how indoor olfactory perception of wildfire smoke is associated with self-reported smoke mitigation behaviors (SMB) and health symptoms. In this work, we analyzed the U.S. Environmental Protection Agency’s (EPA) <em>“Smoke Sense”</em> dataset using Generalized Estimating Equations (GEE), controlling for education, activity level, and percentage of time spent indoors. Compared to smelling smoke outdoors only, smelling smoke both indoors and outdoors significantly increased the odds of adopting SMB and reporting acute health symptoms. These results demonstrate that subjective perception can be leveraged to reduce indoor exposure and “nudge” individual mitigation behaviors. Public health guidance could incorporate outdoor air quality indicators, such as the Air Quality Index (AQI), together with indoor olfactory cues gathered through representative public polling on indoor smoke perception to communicate risks more effectively and support more informed decision-making on indoor smoke mitigation.</div></div>","PeriodicalId":100665,"journal":{"name":"Indoor Environments","volume":"3 1","pages":"Article 100150"},"PeriodicalIF":0.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146037813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Indoor EnvironmentsPub Date : 2026-03-01Epub Date: 2026-02-03DOI: 10.1016/j.indenv.2026.100157
Madeleine Wallace , Saira Prasanth , Alice Egar , Lacee A. Satcher , Samantha Teixeira , Rebekah Levine Coley , Gary Adamkiewicz
{"title":"In-unit particulate matter (PM2.5) in a public housing complex and the importance of tobacco and cannabis as indoor pollutants","authors":"Madeleine Wallace , Saira Prasanth , Alice Egar , Lacee A. Satcher , Samantha Teixeira , Rebekah Levine Coley , Gary Adamkiewicz","doi":"10.1016/j.indenv.2026.100157","DOIUrl":"10.1016/j.indenv.2026.100157","url":null,"abstract":"<div><div>Fine particulate matter (PM<sub>2.5</sub>) is a ubiquitous air pollutant with known socioeconomic disparities in exposure related to both ambient and indoor sources. Understanding how common indoor behaviors such as smoking, cooking, candle or incense burning, and air freshener use contribute to indoor PM<sub>2.5</sub> exposure in public housing can inform interventions to protect residents’ health. PM<sub>2.5</sub> data were collected via PurpleAir monitors for one week within 138 units of a single public housing development in New England, United States and corrected via an additive relative humidity model. Study participants completed a pre-monitoring survey and a post-monitoring survey of in-unit PM<sub>2.5</sub>-related behaviors. Participants’ weekly average in-unit PM<sub>2.5</sub> levels were variable, ranging from 3.6 µg/m<sup>3</sup> to 142.0 µg/m<sup>3</sup>, with a mean of 19.7 µg/m<sup>3</sup>. Two-thirds (65.9%) of households’ average levels exceeded the EPA annual outdoor standard of 9 µg/m<sup>3</sup>, a heuristic reference given the lack of national indoor guidelines. A multivariable model predicting in-unit average PM<sub>2.5</sub> based on resident behaviors found significant associations between elevated PM<sub>2.5</sub> and past-week tobacco smoking (121% higher PM<sub>2.5</sub>), weekly or more cannabis use (56% higher), and living in an apartment building rather than a townhome (26% higher). Cannabis use, which is studied here for the first time in an uncontrolled residential setting, may represent an underappreciated risk factor for exposure. Interventions directed at mitigating indoor smoking of both tobacco and cannabis may be effective at reducing average in-unit PM<sub>2.5</sub> exposure in multifamily housing, as compared to combatting other known indoor sources of PM<sub>2.5</sub>.</div></div>","PeriodicalId":100665,"journal":{"name":"Indoor Environments","volume":"3 1","pages":"Article 100157"},"PeriodicalIF":0.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146188811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Indoor EnvironmentsPub Date : 2025-12-01Epub Date: 2025-12-04DOI: 10.1016/j.indenv.2025.100142
Sirpa Rautiala, Tuula Liukkonen, Pirjo Korenius, Kari Salmi, Päivi Isokääntä, Maria Hirvonen
{"title":"Measured and perceived indoor environmental quality in process control rooms and offices of production facilities","authors":"Sirpa Rautiala, Tuula Liukkonen, Pirjo Korenius, Kari Salmi, Päivi Isokääntä, Maria Hirvonen","doi":"10.1016/j.indenv.2025.100142","DOIUrl":"10.1016/j.indenv.2025.100142","url":null,"abstract":"<div><div>Limited data exists on indoor environmental quality (IEQ) of process control rooms and offices of production facilities. We investigated the IEQ in the process control rooms and offices of seven metal and forest industry facilities in Finland. Furthermore, 538 employees participated in a questionnaire aimed at assessing the prevalence of indoor environment-related (IE-related) complaints and symptoms. The results indicate that the ventilation was sufficient in 89 % of the process control rooms and offices studied, but in 9 %, the air supply was not functioning at all. The physical and chemical parameters complied with relevant requirements, standards, and national reference values in most of the process control rooms and offices. The concentrations of man-made mineral fibers (MMVFs) were high, and moisture damage was more frequently observed compared to other Finnish workplaces. Noise, smells, and impurities from the production processes were found to migrate into the process control rooms and offices. The majority of employees reported IE-related complaints, particularly those working in the process control rooms. The prevalence of symptoms was not higher than that observed among Finnish office employees in non-industrial workplaces. To our knowledge, this study is the first to present data on the IEQ of process control rooms and offices of production facilities. The findings suggest that, although the IEQ was at a satisfactory level in most process control rooms and offices, ventilation issues and the production process can adversely affect the IEQ and employees' perceptions. Future studies in production facilities across other industries and larger datasets are necessary.</div></div>","PeriodicalId":100665,"journal":{"name":"Indoor Environments","volume":"2 4","pages":"Article 100142"},"PeriodicalIF":0.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145684130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Indoor residential pesticide fate, transport, and exposure model","authors":"Noshin Anjum Kamal , Raghavendhran Avanasi , Carrie Huffman , Raj Saran , Tharacad Ramanarayanan , Deborah H. Bennett , Hyeong-Moo Shin","doi":"10.1016/j.indenv.2025.100122","DOIUrl":"10.1016/j.indenv.2025.100122","url":null,"abstract":"<div><div>A deeper understanding of the fate, transport, and exposure of indoor pesticides is needed, especially for application methods specific to indoor environments, such as perimeter and crack-and-crevice treatments. This study addresses this research need by investigating indoor dynamics of pesticides and estimating residential pesticide exposures. For four widely-used pesticides with diverse chemical properties, we refined and applied our multi-compartment indoor fate, transport, and exposure model to simulate time-dependent concentrations across multiple media, integrating exposures over 1- and 30-day periods. Our model shows that when pesticides are applied to floor edges, < 1 % of the total applied mass is transported from treated areas to air or untreated surfaces over 30 days of simulation. Because of limited measurement data for robust model validation, we compared our model’s estimates to those from the U.S. Environmental Protection Agency’s Standard Operating Procedures (SOPs) regulatory model. Comparison revealed that our model’s total exposure estimates are 2–5 orders of magnitude lower than those from the SOP model. Notably, even greater differences were observed for individual exposure routes, as the SOP model does not account for chemical properties but assumes that a fixed daily fraction of the applied mass is available for exposure. In contrast, our model accounts for chemical-specific fate and transport processes. This study highlights the critical role of incorporating chemical fate and transport in residential pesticide exposure assessments. However, monitoring studies are needed to validate our model estimates with measurements collected over time from indoor air and surfaces under known application methods and rates.</div></div>","PeriodicalId":100665,"journal":{"name":"Indoor Environments","volume":"2 4","pages":"Article 100122"},"PeriodicalIF":0.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145050502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}