Effects of thermal discomfort in an office on perceived air quality, SBS symptoms, physiological responses, and human performance

Prevalence of occupational heat stress across the seasons and its management amongst healthcare professionals in the UK

Occupational heat stress (OHS) is an issue in healthcare facilities (HCFs) in the United Kingdom (UK). The aims of this study were to evaluate perceived levels of OHS during two seasons and its perceived consequences on healthcare professionals (HCPs) and to assess the efficacy of heat stress management (HSM) policies. An anonymous online survey was distributed to HCPs working in HCFs in the UK. The survey returned 1014 responses (87% women). Descriptive statistics and content analysis of survey data identified that OHS in HCFs is frequently experienced throughout the year and concerned most HCPs. Over 90% perceived OHS impairs their performance and 20% reported heat-related absenteeism. Awareness of HSM policies was poor and 73% deemed them not adequate. To help reduce the financial loss and impact on staff performance, health and well-being and patient safety, it is recommended that revisions and widespread dissemination of HSM policies are made.

Effects of temperature cycles on human thermal comfort in built environment under summer conditions

Dynamic temperature control strategies are feasible for enhancing energy flexibility and reducing energy consumption in buildings. However, guidelines for designing such dynamic thermal environments are lacking. In this study, 30 participants were recruited to undergo four experimental cycles formed by combining two temperature ranges (25-28 °C and 26-29 °C) and two temperature change rates (3 °C/h and 6 °C/h). Variations in the subjective perception and physiological responses with time were recorded throughout the experiments. The participants reported cooler thermal sensation and better thermal comfort for the same temperature during the ramp-down phase than during the ramp-up phase, which was more pronounced at faster temperature changes. The limits on temperature variations in the current standards underestimate the thermal acceptability of people. Although the temperature cycles exceeded the limits in the standards, sustained thermal comfort and high thermal acceptability were achieved when the temperature changed within 25-28 °C. At a rapid 6 °C/h change rate, the thermal sensation briefly deviated from the comfort zone when Top changed within 26-29 °C, suggesting that the limits should be set relative to the temperature change span. The comfortable temperature ranges for change rates of 3 °C/h and 6 °C/h in summer conditions were 22.8-28.7 °C and 22.8-28.4 °C, respectively, which are broader than the recommended indoor temperature range for summer in the Chinese standard. These findings indicate the potential of temperature variations to extend the thermal comfort zones while consuming less energy without requiring additional cooling devices.

Effects of wearing medical gowns at different temperatures on the physiological responses of female healthcare workers during the COVID-19 Pandemic

BACKGROUND

Using medical gowns with high protection against COVID-19 among healthcare workers (HCWs) may limit heat exchange, resulting in physiological challenges.

OBJECTIVE

This study aimed to compare the physiological and neurophysiological responses of female HCWs when using two typical medical gowns at different temperatures during the COVID-19 pandemic.

METHODS

Twenty healthy female HCWs participated in this study. Participants wore two types of medical gowns: Spunbond gown (SG) and laminate gown (LG). They walked on a treadmill in a controlled climate chamber for 30 minutes at three different temperatures (24, 28, and 32°C). Heart rate (HR), skin surface temperature (ST), clothing surface temperature (CT), ear temperature (ET), blood oxygen percentage (SaO2), galvanic skin response (GSR), and blood pressure were measured before and after walking on a treadmill. The study's results were analyzed using SPSS26.

RESULTS

The study found that LG led to an average increase of 0.575°C in CT compared to SG at the same temperatures (P <  0.03). The average HR increased by 6.5 bpm in LG at 28°C compared to SG at a comfortable temperature (P = 0.01). The average ET in SG and GSR in LG at 32°C increased by 0.39°C and 0.25μS, respectively, compared to the comfortable temperature (P <  0.02).

CONCLUSION

The study recommends maintaining a comfortable temperature range in hospitals to prevent physiological challenges among HCWs wearing medical gowns with high protection against COVID-19. This is important because using LG, compared to SG, at high temperatures can increase HR, ET, CT, and GSR.

Physiology or Psychology: What Drives Human Emissions of Carbon Dioxide and Ammonia?

Humans are the primary sources of CO2 and NH3 indoors. Their emission rates may be influenced by human physiological and psychological status. This study investigated the impact of physiological and psychological engagements on the human emissions of CO2 and NH3. In a climate chamber, we measured CO2 and NH3 emissions from participants performing physical activities (walking and running at metabolic rates of 2.5 and 5 met, respectively) and psychological stimuli (meditation and cognitive tasks). Participants' physiological responses were recorded, including the skin temperature, electrodermal activity (EDA), and heart rate, and then analyzed for their relationship with CO2 and NH3 emissions. The results showed that physiological engagement considerably elevated per-person CO2 emission rates from 19.6 (seated) to 46.9 (2.5 met) and 115.4 L/h (5 met) and NH3 emission rates from 2.7 to 5.1 and 8.3 mg/h, respectively. CO2 emissions reduced when participants stopped running, whereas NH3 emissions continued to increase owing to their distinct emission mechanisms. Psychological engagement did not significantly alter participants' emissions of CO2 and NH3. Regression analysis revealed that CO2 emissions were predominantly correlated with heart rate, whereas NH3 emissions were mainly associated with skin temperature and EDA. These findings contribute to a deeper understanding of human metabolic emissions of CO2 and NH3.

Developing a WELL building model for office environments

Many reported cases of occupants in modern office buildings suffer from severe health risks, negative impacts on well-being, and productivity loss. Existing building standards often prioritize energy performance and green environments over human sustainability. Moreover, office buildings have a distinct group of occupants that require extra attention. Hence, the study aims to develop a WELL building model specifically for office buildings to support occupants' well-being, health, and productivity (i.e., WELL). To achieve that objective, this study developed a list of physical indoor building features through a systematic literature review and semi-structured interviews. Then, the features were inserted into a survey and sent to office building occupants and built environment professionals. The collected data was analyzed using the analytic hierarchy process (AHP) and confirmatory factor analysis (CFA). The findings suggest twelve new features applicable for supporting WELL in office buildings: workspace privacy, sufficient space, office layout, cleanliness, efficiency in building services, individual control, building automation system, Information Technology (IT) infrastructure, Wireless Fidelity (WiFi) risk, security system, safety at parking lots, and safe design. Also, three new concepts for supporting WELL in office buildings were established: office space, building services and maintenance, and smart systems. The new concepts and features lay a foundation for designing office buildings that comprehensively target occupants' WELL. Finally, this study is unique as it accentuates the development of a WELL building model specifically for office buildings.

Indicators to support local public health to reduce the impacts of heat on health

Heat exposure presents a significant weather-related health risk in England and Wales, and is associated with acute impacts on mortality and adverse effects on a range of clinical conditions, as well as increased healthcare costs. Most heat-related health outcomes are preventable with health protection measures such as behavioural changes, individual cooling actions, and strategies implemented at the landscape level or related to improved urban infrastructure. We review current limitations in reporting systems and propose ten indicators to monitor changes in heat exposures, vulnerabilities, heat-health outcomes, and progress on adaptation actions. These indicators can primarily inform local area decision-making in managing risks across multiple sectors such as public health, adult and social care, housing, urban planning, and education. The indicators can be used alongside information on other vulnerabilities relevant for heat and health such as underlying morbidity or housing characteristics, to prioritise the most effective adaptation actions for those who need it the most.

Cooling vest improves surgeons' thermal comfort without affecting cognitive performance: a randomised cross-over trial

OBJECTIVES

Surgeons become uncomfortable while performing surgery because heat transfer and evaporative cooling are restricted by insulating surgical gowns. Consequently, perceptions of thermal discomfort during surgery may impair cognitive performance. We, therefore, aimed to evaluate surgeons' thermal comfort, cognitive performance, core and mean skin temperatures, perceptions of sweat-soaked clothing, fatigue and exertion with and without a CoolSource cooling vest (Cardinal Health, Dublin, Ohio, USA).

METHODS

Thirty orthopaedic surgeons participated in a randomised cross-over trial, each performing four total-joint arthroplasties with randomisation to one of four treatment sequences. The effects of cooling versus no cooling were measured using a repeated-measures linear model accounting for within-subject correlations.

RESULTS

The cooling vest improved thermal comfort by a mean (95% CI) of -2.1 (-2.7 to -1.6) points on a 0-10 scale, p<0.001, with no evidence of treatment-by-period interaction (p=0.94). In contrast, cooling had no perceptible effect on cognition, with an estimated mean difference (95% CI) in Cleveland Clinic Cognitive Battery (C3B) Processing Speed Test score of 0.03 (95% CI -2.44 to 2.51), p=0.98, or in C3B Visual Memory Test score with difference of 0.88 (95% CI -2.25 to 4.01), p=0.57. Core temperature was not lower with the cooling vest, with mean difference (95% CI) of -0.13 (-0.33°C to 0.07°C), p=0.19, while mean skin temperature was lower, with mean difference of -0.23 (95% CI -0.40°C to -0.06°C) lower, p=0.011. The cooling vest significantly reduced surgeons' perceptions of sweat-soaked clothing, fatigue and exertion.

CONCLUSIONS

A cooling vest worn during surgery lowered core and skin temperatures, improved thermal comfort, and decreased perceptions of sweating and fatigue, but did not improve cognition. Thermal discomfort during major orthopaedic surgery is thus largely preventable, but cooling does not affect cognition.

TRIAL REGISTRATION NUMBER

NCT04511208.

Human thermal physiological response of wearing personal protective equipment: An educational building semi-open space experimental investigation

With the outbreak and spread of the COVID-19 epidemic, HCWs are frequently required to wear personal protective equipment (PPE) for nucleic acid sample collection in semi-open transition spaces. Wearing PPE causes significant psychological and physical stress in HCWs. In this study, operative temperature (T_op) and wet-bulb globe temperature (WBGT) were used to assess thermal conditions through field experiments, while multiple physiological parameters were measured in the subjects. The results indicated that the subjects showed statistically significant differences in thermal perception and physiological parameters with and without PPE. Using observed increases in heart rate (HR), auditory canal temperature (T_ac), mean skin temperature (MST), and end-tidal CO₂ pressure, subjects were shown to have an increased metabolic rate and heat storage while wearing PPE. Additionally, a decrease in oxygen concentration was also observed, and this decrease may be linked to fatigue and cognitive impairment. Moreover, HR, MST, and T_ac showed a significant linear relationship, which increased with temperature and operative temperature, and the HR response was stronger with PPE than without PPE. The neutral, preferred, and acceptable temperatures were significantly lower with PPE than without PPE, and the deviations for neutral T_op/WBGT were 9.5/7.1 °C and preferred T_op/WBGT was 2.2/4.0 °C, respectively. Moreover, the upper limits of acceptable WBGT, 29.4 °C with PPE and 20.4 °C without PPE, differed significantly between the two phases. Furthermore, the recorded physiological parameter responses and thermal perception responses of the subjects while wearing PPE indicated that they were at risk of thermal stress. Overall, these results suggest that people who wear PPE should focus on their health and thermal stress. This study provides a reference for the development of strategies to counteract heat stress and improve thermal comfort.

Indoor thermal comfort research using human participants: Guidelines and a checklist for experimental design

Thermal comfort dictates our alliesthesia and behavioural responses in indoor environments with the primary aim of maintaining the thermal homeostasis of our human body. The recent advances in neurophysiology research have suggested that thermal comfort is a physiological response that is regulated by the deviations of both skin and core temperatures. Therefore, when conducting thermal comfort using indoor occupants in an indoor environment, proper experimental design and standardisation should be followed. However, there is no published source that provides an educational guideline on how to properly implement the thermal comfort experiment in an indoor environment using indoor occupants (normal occupational activities and during sleep in a home-based setting). Therefore, the primary purpose of this work is to illustrate how to conduct indoor thermal comfort related experiments using human trials in both normal occupational activities and during sleep in a home-based setting. Furthermore, we hope that the information presented in this article will result in better experimental design when conducting the experiment on thermal comfort using indoor occupants (occupational and home-based environments). Due to this reason, special emphasis will be focused on the experimental design, selection of participants and experimental standardisation. The key summary of this article is that thermal comfort related to indoor occupants in an indoor environment should perform priori sample analysis and follow the proper experimental design and standardisation as outlined in this article.

Impact of high temperature on road injury mortality in a changing climate, 1990-2019: A global analysis

BACKGROUND

Previous studies have shown that extreme heat likely increases the risk of road injuries. However, the global burden of road injuries due to high temperature and contributing factors remain unclear. This study aims to characterize the global, regional and national burden of road injuries due to high temperature from 1990 to 2019.

METHODS

Based on the Global Burden of Disease (GBD) study 2019, we obtained the numbers and age-standardized mortality rates (ASMR) and age-standardized disability-adjusted life years (DALY) rates (ASDR) of the road injury due to high temperature at global, regional, and national levels from 1990 to 2019. The world is divided into five climate zones according to the average annual temperature of each country: tropical, subtropical, warm temperate, cold temperate, and boreal. We used the generalized additive models (GAM) to model the trends of road injuries globally and by region.

RESULTS

Globally, between 1990 and 2019, the deaths of road injury attributable to high temperature increased significantly from 20,270 (95% uncertainty interval [UI], 7836 to 42,716) to 28,396 (95% UI, 13,311 to 51,178), and the DALYs increased from 1,169,309 (95% UI, 450,834 to 2,491,075) to 1,414,527 (95% UI, 658,347 to 2,543,613). But the ASMR and the ASDR slightly decreased by 8.49% and 13.16%, respectively. The burden of road injury death attributable to high temperature remained high in low SDI and tropical regions. In addition, road transport infrastructure investment per inhabitant is associated with the burden of road injuries attributable to high temperature.

CONCLUSIONS

Globally, the ASMR and ASDR for road injuries attributable to high temperature decreased from 1990 to 2019, but the absolute death and DALYs continued to increase. Thus, concerning global warming, implementation of prevention and interventions to reduce road injuries from heat exposure should be stressed globally.

Thermal perception and lung function: a panel study in young adults with exercise under high outdoor temperature

It has been observed that high temperature exposure is associated with a reduction in lung function and some possible biological mechanisms have been suggested. However, it is unclear if thermal perception plays a role in the association. From September 3rd to 15th, 2018, in Guangzhou, China, we repeatedly measured daily thermal perception and lung function among 126 participants with outdoor military training. We performed a linear mixed model and stratified analyses by the origin of students, gender, and the training period to evaluate the effects of thermal perception on lung function. A total of 399 measurements were collected. Per vote increase in thermal sensation vote towards the "hot" direction was associated with a - 0.04 L (95% CI: - 0.08 to - 0.01) decrease in forced vital capacity (FVC), and - 0.04 L (95% CI: - 0.08 to - 0.01) decrease in forced expiratory volume in 1 s (FEV₁). Per grade increase towards the "very uncomfortable" direction for thermal comfort vote was associated with an increased percentage of forced expiratory volume in 1 s (FEV₁%) by 1.52% (95% CI: 0.18 to 2.86). For thermal preference, with preferred cooler vote increased by one level, FVC and FEV₁ decreased by - 0.05 L/s (95% CI: - 0.08 to - 0.02) and - 0.05L/s (95% CI: - 0.08 to - 0.02), respectively. The effects of thermal perception on lung function were stronger among non-local and in the first week of training. Our study suggests that in the same high-temperature environment, thermal perception is associated with lung function, even in healthy adults.

Evaluating machine learning models to classify occupants' perceptions of their indoor environment and sleep quality from indoor air quality

A variety of factors can affect a person's perception of their environment and health, but one factor that is often overlooked in indoor settings is the air quality. To address this gap, we develop and evaluate four Machine Learning (ML) models on two disparate datasets using Indoor Air Quality (IAQ) parameters as primary features and components of self-reported IAQ satisfaction and sleep quality as target variables. In each case, we compare models to each other as well as to a simple model that always predicts the majority outcome. In the first analysis, we use open-source data collected from 93 California residences to predict occupant's satisfaction with their indoor environment. Results indicate building ventilation rate, Relative Humidity (RH), and formaldehyde are most influential when predicting IAQ perception and do so with an accuracy greater than the simplified model. The second analysis uses IAQ data gathered from a field study we conducted with 20 participants over 11 weeks to train similar models. We obtain accuracy and F1 scores similar to the simplified model where PM_2.5 and TVOCs represent the most important predictors. Our results underscore the ability of IAQ to affect a person's perception of their built environment and health and highlight the utility of ML models to explore the strength of these relationships.Implications: The results from this study show that two outcome variables - occupant's indoor air quality (IAQ) satisfaction and perceived sleep quality - are related to the measured IAQ parameters but not heavily influenced by typical values measured in apartments and homes. This study highlights the ability of machine learning models as exploratory analysis tools to determine underlying relationships within and across datasets in addition to understanding the importance of certain features on the outcome variable. We compare four different models and find that the random forest classifier has the best performance in both analysis on IAQ satisfaction and perceived sleep quality. It is a suitable model for predicting IAQ-related subjective metrics and also provides value insight into the feature importance of the IAQ parameters. The accuracy of any of these machine learning models in predicting occupants' comfort or sleep quality is limited by the dataset size, how data is collected, and range of data. This study identifies the factors that are important to IAQ perception: ventilation rate, relative humidity, and concentrations of formaldehyde, NO2, and particulate matter. It indicates that sensors that can measure these variables are necessary for future, related studies that model occupants' IAQ satisfaction. However, this study does not find strong relationships between any of the IAQ parameters measured in this study and perceived sleep quality despite the logical pathway between these many pollutants and respiratory issues. A prediction model of IAQ perception or sleep quality can be integrated into home management systems to automatically adjust building operations such as ventilation rates in smart buildings. Once buildings are equipped with a network of low-cost sensors that measure concentrations of pollutants and operating conditions of the ventilation system, the prediction model can be used to predict the occupants' comfort and facilitate the control of the ventilation system.

Effects of occupant behaviors on perceived dormitory air quality and sick building syndrome symptoms among female college students

We performed a cross-sectional survey of 2143 female students in a university in Tianjin, China regarding perceived air quality (PAQ) and sick building syndrome (SBS) symptoms in the student dormitory. The prevalence of general, mucosal, and skin symptoms was 22.1%, 21.9%, and 26.3%, respectively. The three most prevalent PAQ complaints were "dry air" (48.9% often), "stuffy odor" (18.2%), and "other unpleasant odors" (5.1%), and they were significant risk factors for 11-12 out of 12 SBS symptoms (adjusted odds ratios [AOR]: 1.6-5.8). Survey data of 1471 undergraduates, whose dorms were of uniform layout and furnishing, were used to further investigate the influences of occupancy level and occupant behaviors on PAQ and SBS symptoms. Frequent use of air freshener/perfume was a significant risk factor for "dry air," less frequent room cleaning and higher occupancy density were significant risk factors for "stuffy odor," and less natural ventilation was a significant risk factor for both "stuffy odor" and "pungent odor." These factors were also significantly associated with some SBS symptoms. In particular, the use of air freshener/perfume exhibited a significant dose-response pattern with "fatigue" (sometimes: AOR 1.3; often: AOR 2.0) and with "irritated, stuffy, or runny nose" (sometimes: AOR 1.6; often: AOR 2.2).

Feasibility of High-Frequency Monitoring of the Home Environment and Health in Older Adults: Proof of Concept

Technology provides new opportunities to understand and optimize the relationship between the home indoor environmental quality and health outcomes in older adults. We aimed to establish proof-of-concept and feasibility of remote, real-time, high-frequency, and simultaneous monitoring of select environmental variables and outcomes related to health and wellbeing in older adults. Thirty-four participants (27 were female) with an average age (SD) of 81 years (±7.1) were recruited from community and supportive housing environments. Environmental sensors were installed in each home and participants were asked to use a wearable device on their finger and answer smartphone-based questionnaires on a daily basis. Further, a subgroup of participants were asked to complete tablet-based cognitive tests on a daily basis. Average compliance with the wearable (time worn properly / total time with device) was 81%. Participants responded to 69% of daily smartphone surveys and completed 80% of the prescribed cognitive tests. These results suggest that it is feasible to study the impact of the home thermal environment and air quality on biological rhythms, cognition, and other outcomes in older adults. However, the success of non-passive data collection elements may be contingent upon baseline cognition.

Influence of Face Mask and Tropical Climate on Subjective States: Affect, Motivation, and Selective Attention

We investigated whether face mask wearing in a hot and humid environment would influence subjective states: motivation, affect, and the performance of cognitive tasks requiring attentional processes. Forty volunteers performed the tasks under 4 repeated conditions: in an air-conditioned (AC) room or a tropical climate (TC; hot and wet environment) while wearing a mask or not (counterbalanced). For each condition, they completed questionnaires on subjective states (affect, motivation, and attentional processes) by performing the Bells and d2 tests, and a comparison of men and women was an indirect focus of this study. Results showed that the participants had higher sensations of fatigue, thermal discomfort, and a negative affect when wearing a mask in the TC condition. Additionally, lower performance scores were noted in the Bells test when participants wore a mask in a TC compared with all other conditions. Lastly, the participants’ performance on the d2 test involving selective and sustained attention improved without a mask in AC and in TC conditions. Consequently, the results revealed that wearing a mask in a TC can induce anxiety, headaches, discomfort, and lower motivation.

Pursuing occupants' health and well-being in building management: Definition of new metrics based on indoor air parameters

The spread of COVID-19 has affected the lives of millions of people. Pandemic has made people more sensitive to health issues. In particular, the growing concern for the virus spread in confined spaces has promoted the necessity to improve indoor air quality. Literature is stressing how buildings must be designed and operated pursuing occupants' health and well-being, with a particular attention for indoor air parameters. This poses the challenge of monitoring and assessing these aspects through proper metrics. In this paper the approach towards a multi-step assessment procedure embedding in buildings assessment health and well-being related variables and indicators is elaborated. They are intended to inform a building manager of the potential influence of air conditions on human health and well-being. Moreover, a set of monetary metrics (i.e., impacts) is proposed to translate energy and indoor air related building performances into euros, putting the basis for a comprehensive economic evaluation. The application of the set of proposed metrics to an Italian hotel (i.e., Italian pilot of H2020 MOBISTYLE project), enabled to map some indoor air conditions causing health concerns, and to identify clusters of guests with best and worst indoor air conditions, to be targeted by new management strategies. Despite case study specific limitations, the application exemplified how the methodology can expand the traditional energy-based performance assessment for building management towards indoor air domain and the related economic impacts, with implication on results in terms of overall economic performance of the building from both a private and public perspective.

AI-enabled prediction of video game player performance using the data from heterogeneous sensors

The emerging progress of video gaming and eSports lacks the tools for ensuring high-quality analytics and training in professional and amateur eSports teams. We report on an Artificial Intelligence (AI) enabled solution for predicting the eSports player in-game performance using exclusively the data from sensors. For this reason, we collected the physiological, environmental, and the smart chair data from professional and amateur players. The player performance is assessed from the game logs in a multiplayer game for each moment of time using a recurrent neural network. We have investigated an attention mechanism improves the generalization of the network and provides a straightforward feature importance as well. The best model achieves Area Under the Receiver Operating Characteristic Curve (ROC AUC) score 0.73 in predicting whether a player will perform better or worse in the next 240 seconds based on in-game metrics. The prediction of the performance of a particular player is realized although their data are not utilized in the training set. The proposed solution has a number of promising applications for professional eSports teams and amateur players, such as a learning tool or performance monitoring system.

The effect of inhaled air temperature on thermal comfort, perceived air quality, acute health symptoms and physiological responses at two ambient temperatures

We explored the importance of inhaled air temperature on thermal comfort, perceived air quality, acute non-clinical health symptoms, and physiological responses. Sixteen subjects stayed in a stainless-steel chamber for 90 min. They experienced four conditions with two inhaled air temperatures of 22 and 30°C and two ambient temperatures of 22 and 30°C in a 2 × 2 design. They wore breathing masks covering their mouth and nose to control the inhaled air temperature; the air was provided from an adjacent twin stainless-steel chamber. The subjects evaluated thermal conditions and health symptoms on visual-analogue scales. Skin temperature and electrocardiography were recorded. Whole-body thermal sensation and skin temperature did not change when the temperature of inhaled air was changed. Perceived air quality was significantly improved when subjects sat in the chamber at 30°C and inhaled air with a temperature of 22°C; under these conditions lip and throat dryness were significantly reduced. The lower inhaled air temperature increased time-domain heart rate variability indicators and decreased heart rate and the LF/HF ratio, suggesting that the parasympathetic nervous system was activated and the sympathetic nervous system was suppressed.

Effect of adaptive opportunity on cognitive performance in warm environments

This study investigates the hypothesis that thermal adaptive opportunities available to building occupants affect their cognitive performance and mental workload. The change rate of cerebral blood flow (Δtotal Hb) was measured by Near Infra-Red Spectroscopy (NIRS) and interpreted as the metric of mental workload in subjects while performing cognitive tasks (n-back tests) with, or without access to thermal adaptive opportunities such as regulable fan-induced air flow and clothing insulation adjustment. Participants underwent three experimental conditions: Condition 22 (operative temperature t_o = 22 °C without adaptive opportunities), Condition 28 (t_o = 28 °C without adaptive opportunities), and Condition 28w (t_o = 28 °C with adaptive opportunities. Under Condition 28w, thermal sensations were neutral, while thermal satisfaction and comfort levels were higher than those reported for Condition 28, and the same as those reported under Condition 22. The subjects' mean skin temperature under Condition 22 was the lowest at 32.1 °C, followed by Condition 28w at 33.6 °C, while the highest, 34.5 °C was recorded in Condition 28. No significant differences were observed in accuracy and reaction time of n-back tests between the three different environmental conditions. Under Condition 28w, mental fatigue levels and the left side Δ total Hb results were lowest out of all three conditions, although the differences failed to reach statistical significance. Availability of adaptive opportunities plays a role in expanding the range of thermal environmental conditions for optimal cognitive task performance in a moderately warm environment (t_o = 28 °C). This finding cannot be fully explained by the direct effect of adaptive behaviours on human heat balance and associated physiological responses, but the unexplained component may potentially be attributed to the psychological dimension of human adaptive response. These findings and their interpretation within an adaptive comfort framework are consistent with the extended-U hypothesis of cognitive performance.

An Experimental Study of Thermal Comfort and Indoor Air Quality—A Case Study of a Hotel Building

Ensuring the comfort and health of occupants is the main objective of properly functioning building systems. Regardless of the season and building types, it is the priority of the designers and building managers. The indoor air parameters affect both the well-being and health of users. Furthermore, it could impact the effectiveness of their work and concentration abilities. In hotel facilities, the guests’ comfort is related directly to positive opinions or customer complaints, which is related to financial benefits or losses. The main goal of this study is the analysis of the indoor environmental quality in guests’ rooms, based on the example of a hotel in Poland. The article assesses the variability of air parameters, including temperature, humidity, and carbon dioxide concentrations, and the acceptability of indoor conditions. The research was carried out in November 2020. Based on the collected data, the dynamics of changes of selected air parameters were analyzed. The article analyzes the comfort indicators inside guest rooms, including the Predicted Mean Vote (PMV) and Predicted Percentage of the Dissatisfied (PPD) index. The obtained results were compared with the optimal conditions of use to ensure the guests’ comfort. As the analysis showed, the temperature and humidity conditions are maintained at a satisfactory level for most of the time. It was noticed that the CO2 concentrations temporarily exceeded the value of 2000 ppm in two of the analyzed guests’ rooms, which could cause discomfort to hotel guests. In these rooms, the increase in the volume of ventilation airflow should be considered. The measured parameters dynamically varied over time, and there was no repeatability or clear patterns of variation. This is due to the individual preferences and behavior of users. A detailed analysis is extremely difficult due to the possibility of opening windows by users, the irregular presence of hotel guests in the rooms, and the inability to verify the exact number of users in the room during the measurements.

Effects of a cool classroom microclimate on cardiac autonomic control and cognitive performances in undergraduate students

An inverted U-shape relationship between cognitive performance and indoor temperature with best performance peaking at 21.6 °C was previously described. Little is known on classroom temperature reduction effects on cognitive performances and cardiac autonomic profile, during the cold season. Fifteen students underwent electrocardiogram recording during a lecture in two days in December when classroom temperatures were set as neutral (NEUTRAL, 20-22 °C) and cool (COOL, 16-18 °C). Cognitive performance (memory, verbal ability, reasoning, overall cognitive C-score) was assessed by Cambridge Brain Science cognitive evaluation tool. Cardiac autonomic control was evaluated via the analysis of spontaneous fluctuations of heart period, as the temporal distance between two successive R-wave peaks (RR). Spectral analysis provided the power in the high frequency (HF, 0.15-0.40 Hz) and low frequency (LF, 0.04-0.15 Hz) bands of RR variability. Sympatho-vagal interaction was assessed by LF to HF ratio (LF/HF). Symbolic analysis provided the fraction of RR patterns composed by three heart periods with no variation (0 V%) and two variations (2 V%), taken as markers of cardiac sympathetic and vagal modulations, respectively. The students' thermal comfort was assessed during NEUTRAL and COOL trials. Classroom temperatures were 21.5 ± 0.8 °C and 18.4 ± 0.4 °C during NEUTRAL and COOL. Memory, verbal ability, C-Score were greater during COOL (13.01 ± 3.43, 12.32 ± 2.58, 14.29 ± 2.90) compared to NEUTRAL (9.98 ± 2.26, p = 0.002; 8.57 ± 1.07, p = 0.001 and 10.35 ± 3.20, p = 0.001). LF/HF (2.4 ± 1.7) and 0 V% (23.2 ± 11.1%) were lower during COOL compared to NEUTRAL (3.7 ± 2.8, p = 0.042; 28.1 ± 12.2.1%, p = 0.031). During COOL, 2 V% was greater (30.5 ± 10.9%) compared to NEUTRAL (26.2 ± 11.3, p = 0.047). The students' thermal comfort was slightly reduced during COOL compared to NEUTRAL trial. During cold season, a better cognitive performance was obtained in a cooler indoor setting enabling therefore energy saving too.

Exploring the Impact of Green Walls on Occupant Thermal State in Immersive Virtual Environment

Green walls have been used in built environments as a natural element to bring various benefits, thus improving human health and well-being. However, in conventional virtual environments, the visual connection with a green wall is the only way that this natural element could benefit humans. Unfortunately, the impact of such visual connection on human thermal perception is still not well understood. Thus, we conducted an experimental study with 40 participants comparing the thermal state of two virtual sessions: biophilic (a room with a green wall) and non-biophilic (the same room without a green wall). Both sessions were conducted in a climate chamber under a slightly warm condition (28.89 °C and 50% relative humidity). Participants’ thermal state, skin temperature, and heart rate data were collected. According to the results, participants’ thermal comfort and hand skin temperature were significantly different between the two sessions, and their mean skin temperature was statistically increased over time. The study suggests that before the extent to which the impact of visual stimuli (e.g., green walls) on thermal perception is fully understood, researchers may need to control visual and thermal stimuli separately when using them in immersive virtual environments. Furthermore, the virtual exposure time should be an important consideration when designing experimental procedures.

Understanding Occupants’ Thermal Sensitivity According to Solar Radiation in an Office Building with Glass Curtain Wall Structure

The thermal comfort of occupants in the increasing number of modern buildings with glass curtain wall structures is of significant research interest. As the thermal sensitivity of building occupants varies with building features, situational factors, and the human body’s thermal balance, it is necessary to derive the comfort temperature based on field research, which was conducted in this study in a South Korean office building with a glass curtain wall structure. The influence of solar radiation on the indoor thermal environment and thermal comfort obtained by measurements and occupant questionnaires was analyzed using cumulative graphs and a sensitivity analysis. The observed changes in operative temperature over time confirmed that occupant comfort was significantly affected by the radiant temperature. Based on this result, two groups (Group A near the windows and Group B near the interior corridor) were defined for analysis. Owing to the influx of solar radiation, Group A was more sensitive to changes in the thermal environment (0.67/°C) than Group B (0.49/°C), and the derived comfort temperature for each group differed from the set temperature by approximately ±2 °C. Thus, it was confirmed that the solar radiation introduced through a glass curtain wall building has a direct impact on the indoor thermal environment and occupant comfort according to location.

Cognitive performance was reduced by higher air temperature even when thermal comfort was maintained over the 24-28°C range

This study managed to create thermal comfort conditions at three temperatures (24°C-T24, 26°C-T26, and 28°C-T28) by adjusting clothing and air velocity. Thirty-six subjects (18 males and 18 females) were exposed to each of the three conditions for 4.5 h in a design balanced for order of presentation of conditions. During each exposure, they rated the physical environment, their comfort, the intensity of acute subclinical health symptoms, and their mental load, and they performed a number of cognitive tasks. Their physiological reactions were monitored. The subjects rated T24 to be comfortably cool, T26 to be comfortably neutral, and T28 to be comfortably warm. Their self-estimated performance did not differ between conditions but 12 of 14 objective metrics of cognitive performance decreased significantly at the elevated temperatures: compared with T24, their average cognitive performance decreased by 10% at T26 and by 6% at T28. At the elevated temperatures, their parasympathetic nervous system activity (as indicated by PNN50) and their arterial blood oxygen saturation level (SpO2) were both lower, which would be expected to result in reduced cognitive performance. The subjects also rated their acute subclinical health symptoms as more intense and their workload as higher at the elevated temperatures. These results suggest that where cognitive performance is the priority, it is wise to ensure a comfortably cool environment. The present study also supports the use of fans or natural ventilation to reduce the need for mechanical cooling.

Occupant health in buildings: Impact of the COVID-19 pandemic on the opinions of building professionals and implications on research

The objectives of this study are to investigate building professionals' experience, awareness, and interest in occupant health in buildings, and to assess the impact of the COVID-19 pandemic on their opinions, as well as to compare the research on occupant health in buildings to professionals' opinions. To address these objectives, a mixed research methodology, including a thorough review of the literature (N_L = 190) and an online survey (N_S = 274), was utilized. In general, there is an increasing research interest in occupant health and a heightened interest in health-related projects, among professionals, following the COVID-19 pandemic. Specifically, among the nine different building attributes examined, indoor air quality was the most researched building attribute with a focus on occupant health and was also presumed to be the most important by the professionals. Professionals considered fatigue and musculoskeletal pain to be the most important physical well-being issues, and stress, anxiety, and depression to be the most important mental well-being issues that need to be the focus of design, construction, and operation of buildings to support and promote occupant health, while eye-related symptoms and loss of concentration were the most researched physical and mental well-being symptoms in the literature, respectively. Finally, professionals indicated that COVID-19 pandemic had significant effect on their perspectives regarding buildings' impact on occupant health and they believed future building design, construction and operation will focus more on occupant health because of the pandemic experience.

The effects of warmth and CO2 concentration, with and without bioeffluents, on the emission of CO2 by occupants and physiological responses

The emission rate of carbon dioxide (CO₂ ) depends on many factors but mainly on the activity level (metabolic rate) of occupants. In this study, we examined two other factors that may influence the CO₂ emission rate, namely the background CO₂ concentration and the indoor temperature. Six male volunteers sat one by one in a 1.7 m³ chamber for 2.5 h and performed light office-type work under five different conditions with two temperature levels (23 vs. 28°C) and three background concentrations of CO₂ (800 vs. 1400 vs. 3000 ppm). Background CO₂ levels were increased either by dosing CO₂ from a cylinder or by reducing the outdoor air supply rate. Physiological responses to warmth, added CO₂ , and bioeffluents were monitored. The rate of CO₂ emission was estimated using a mass-balance equation. The results indicate a higher CO₂ emission rate at the higher temperature, at which the subjects were warm, and a lower emission rate in all conditions in which the background CO₂ concentration increased. Physiological measurements partially explained the present results but more measurements are needed.

Mobile Sensing with Smart Wearables of the Physical Context of Distance Learning Students to Consider Its Effects on Learning

Research shows that various contextual factors can have an impact on learning. Some of these factors can originate from the physical learning environment (PLE) in this regard. When learning from home, learners have to organize their PLE by themselves. This paper is concerned with identifying, measuring, and collecting factors from the PLE that may affect learning using mobile sensing. More specifically, this paper first investigates which factors from the PLE can affect distance learning. The results identify nine types of factors from the PLE associated with cognitive, physiological, and affective effects on learning. Subsequently, this paper examines which instruments can be used to measure the investigated factors. The results highlight several methods involving smart wearables (SWs) to measure these factors from PLEs successfully. Third, this paper explores how software infrastructure can be designed to measure, collect, and process the identified multimodal data from and about the PLE by utilizing mobile sensing. The design and implementation of the Edutex software infrastructure described in this paper will enable learning analytics stakeholders to use data from and about the learners’ physical contexts. Edutex achieves this by utilizing sensor data from smartphones and smartwatches, in addition to response data from experience samples and questionnaires from learners’ smartwatches. Finally, this paper evaluates to what extent the developed infrastructure can provide relevant information about the learning context in a field study with 10 participants. The evaluation demonstrates how the software infrastructure can contextualize multimodal sensor data, such as lighting, ambient noise, and location, with user responses in a reliable, efficient, and protected manner.

Thermoelectric Materials for Textile Applications

Since prehistoric times, textiles have served an important role-providing necessary protection and comfort. Recently, the rise of electronic textiles (e-textiles) as part of the larger efforts to develop smart textiles, has paved the way for enhancing textile functionalities including sensing, energy harvesting, and active heating and cooling. Recent attention has focused on the integration of thermoelectric (TE) functionalities into textiles-making fabrics capable of either converting body heating into electricity (Seebeck effect) or conversely using electricity to provide next-to-skin heating/cooling (Peltier effect). Various TE materials have been explored, classified broadly into (i) inorganic, (ii) organic, and (iii) hybrid organic-inorganic. TE figure-of-merit (ZT) is commonly used to correlate Seebeck coefficient, electrical and thermal conductivity. For textiles, it is important to think of appropriate materials not just in terms of ZT, but also whether they are flexible, conformable, and easily processable. Commercial TEs usually compromise rigid, sometimes toxic, inorganic materials such as bismuth and lead. For textiles, organic and hybrid TE materials are more appropriate. Carbon-based TE materials have been especially attractive since graphene and carbon nanotubes have excellent transport properties with easy modifications to create TE materials with high ZT and textile compatibility. This review focuses on flexible TE materials and their integration into textiles.

Assessment of Indoor Environmental Quality in Budget Hotels Using Text-Mining Method: Case Study of Top Five Brands in China

Guests’ evaluation of indoor environmental quality (IEQ) is important for identifying environment quality problems in hotels and improving service quality. This paper aims to identify IEQ problems in budget hotels in China and improve them. Specifically, 2.06 million online reviews of budget hotels were used to assess IEQ issues in China’s budget hotels in four areas: acoustic environment, luminous environment, indoor air quality (IAQ) and thermal environment. The influences of the season, region and type of customers on the IEQ evaluation were also explored, and the main causes of IEQ problems were also identified. The research results show that the IEQ complaint rates of budget hotels are relatively high. In particular, complaints about the acoustic environment are more common. Differences in seasons and climate zones have significant effects on complaints about the acoustic environment, thermal environment and IAQ. Different types of customers have different concerns about hotel IEQ, among which solo travelers and traveling couples have higher requirements for IEQ. The occurrence of IEQ problems significantly reduces a hotel’s online rating, with IAQ and the thermal environment having the greatest impacts, but the causal factors that trigger IEQ problems are relatively concentrated. The findings of this paper can provide a reference for assessing IEQ problems in hotel buildings and guide hotel managers to adopt targeted IEQ improvement programs to promote sustainable development in the hotel industry.

Experimental study on sleep quality affected by carbon dioxide concentration

This study comprehensively investigated the impact of indoor carbon dioxide (CO₂ ) concentration on sleep quality. Three experimental conditions (800, 1900, 3000 ppm) were created in chambers decorated as bedroom and other environmental parameters that may influence the sleep quality were under strict control. Sleep quality of 12 subjects (6 men and 6 women) was monitored for 54 consecutive days through sleep quality questionnaire and physiological measures. Both subjective and physiological results showed that sleep quality decreased significantly with the increase of CO₂ concentration, and the comprehensive questionnaire score at 3000 ppm was only 80.8% of that at 800 ppm. A linear positive correlation was found between sleep onset latency (SOL) and CO₂ concentration, while a linear negative correlation occurred between slow-wave sleep (SWS) and CO₂ concentration. In addition, in the same sleep environment, men had higher subjective questionnaire scores after wake-up, longer SWS and shorter SOL, which lead to a better sleep quality compared with women, and there was a significant gender difference in sleep quality at 800 ppm (P < .05).

Combined effects of noise and air temperature on human neurophysiological responses in a simulated indoor environment

The aim of the present study was to evaluate the combined effects of noise and air temperature on the human body neurophysiological responses. This study was conducted on 35 male students, who were exposed to four different air temperatures (18 °C, 22 °C, 26 °C, and 30 °C) and two noise levels (55 dBA and 75 dBA) in eight sessions in a simulated indoor environment. The mean values of accuracy and time of response to stimuli in N-back test as well as neurophysiological responses were measured. In the studied experiment configurations, with increasing air temperature and noise, the working memory and neurophysiological responses were disturbed. The results indicated the significant effect of noise on working memory, as compared with that of air temperature. The effects of air temperature on heart rate, respiratory rate as well as theta and alpha bands were more significant than the impact of noise. The combined effects of noise and air temperature were more significant than the influence of each of them alone. In the presence of high noise levels, the increase in air temperature did not worsen the response accuracy. However, in the presence of high noise level, the rise in air temperature aggravated the mean value of neurophysiological responses. Overall, noise has a greater effect on working memory, while the air temperature can disturb neurophysiological responses in a more profound way.

Perceived air quality and cognitive performance decrease at moderately raised indoor temperatures even when clothed for comfort

This study investigated whether adjusting clothing to remain in neutral thermal comfort at moderately elevated temperature is capable of avoiding negative effects on perceived acute subclinical health symptoms, comfort, and cognitive performance. Two temperatures were examined: 23°C and 27°C. Twelve subjects were able to remain thermally comfortable at both temperatures by adjusting their clothing. They rated the physical environment, their comfort, the intensity of acute subclinical health symptoms, and their mental load, and they performed a number of cognitive tasks. Their physiological reactions were monitored. Their performance of several tasks was significantly worse at 27°C, and they reported increased mental load at this temperature. Skin temperature and humidity and respiration rate were higher, while blood oxygen saturation (SpO2) and pNN50 were lower at this temperature, the latter indicating increased stress. It is inferred that the observed physiological responses were mainly responsible for the negative effects on performance, as the subjects did not indicate any increased intensity of acute subclinical health symptoms although perceived air quality was worse at the higher temperature. The present results suggest that moderately elevated temperatures should be avoided even if thermal comfort can be achieved, as it may lead to reduced performance.

A Comprehensive Survey about Thermal Comfort under the IoT Paradigm: Is Crowdsensing the New Horizon?

This paper presents a review of technologies under the paradigm 4.0 applied to the study of the thermal comfort and, implicitly, energy efficiency. The research is based on the analysis of the Internet of Things (IoT) literature, presenting a comparison among several approaches adopted. The central objective of the research is to outline the path that has been taken throughout the last decade towards a people-centric approach, discussing how users switched from being passive receivers of IoT services to being an active part of it. Basing on existing studies, authors performed what was a necessary and unprecedented grouping of the IoT applications to the thermal comfort into three categories: the thermal comfort studies with IoT hardware, in which the approach focuses on physical devices, the mimicking of IoT sensors and comfort using Building Simulation Models, based on the dynamic modelling of the thermal comfort through IoT systems, and Crowdsensing, a new concept in which people can express their sensation proactively using IoT devices. Analysing the trends of the three categories, the results showed that Crowdsensing has a promising future in the investigation through the IoT, although some technical steps forward are needed to achieve a satisfactory application to the thermal comfort matter.

Exposure to indoor air contaminants in school buildings with and without reported indoor air quality problems

Reported indoor air quality (IAQ) complaints are common even in relatively new or renovated school buildings in Finland. However, detecting the causes for complaints with commonly used indoor air measurements is difficult. This study presents data on perceived and measured IAQ in six comprehensive school buildings in Finland. The aim of this study was to discover the possible differences of perceived and measured IAQ between schools with reported IAQ complaints and schools without reported IAQ complaints. The initial categorisation of schools with ('problematic schools') and without ('comparison schools') complaints was ensured via a validated indoor climate survey and a recently developed online questionnaire, which were completed by 186 teachers and 1268 students from the six schools. IAQ measurements of physical parameters, gaseous pollutants, particulate matter and bioaerosols were conducted in four problematic school buildings (26 classrooms) and two comparison school buildings (12 classrooms). Using air sampling as well as exhaust air filters and classroom settled dust to detect the presence of elevated concentrations of airborne cultivable microbes and pathogenic, toxigenic and mycoparasitic Trichoderma strains were the most indicative methods in distinguishing problematic schools from comparison schools. Other IAQ-related measurements did not detect clear differences between problematic and comparison schools, as the concentration levels were very low. The results indicate that the complaints reported by occupants could have been related to excess moisture or mould problems that had not been found or repaired. Ventilation pressure condition investigations and simultaneous exhaust and supply air filter dust culture should be addressed precisely in future studies.

Impact of Cold Water Intake on Environmental Perceptions, Affect, and Attention Depends on Climate Condition

The use of cooling techniques in a tropical climate can limit the increase in core body temperature and therefore improve physical exercise performance. However, little is known about the impact of cooling on psychological functioning. The aim of this study was to determine whether cold water intake influences environmental perceptions, affects, and attention depending on the climate condition (tropical climate vs. neutral climate). The study followed a mixed 2 × 3 crossover design (climate as the within factor, tropical climate vs. neutral climate; water intake as the between factor, cold water vs. neutral water vs. no water). Participants reported lower thermal comfort, had positive affect scores, had lower attention performance scores, and had higher thermal sensation and negative affect in tropical climate compared with neutral climate. It was shown that drinking water at room temperature in a neutral climate causes the best thermal comfort scores, and drinking water at room temperature in tropical climate causes the worst scores. Cold water intake, which had no notable influence on positive affect scores in a tropical climate, had a deleterious effect in a neutral climate. Drinking cold water as a technique to limit the deleterious effects of tropical climate on environmental perceptions, affect, and attention is discussed.

Air Enthalpy as an IAQ Indicator in Hot and Humid Environment—Experimental Evaluation

The authors studied the impact of indoor air humidity in the range of 60% to 90% on building user perception in the temperature range of 26 to 28 °C. The research thesis was put forward that the impact of humidity on indoor air quality dissatisfaction of building users in a warm and humid indoor environment is greater than that indicated in thermal comfort models. The presented experiment examined the indoor air quality perception of n = 28 subjects in the test chamber of a nearly zero energy building under ten environmental conditions, together with a thermal comfort assessment. The authors developed an experimental relation for predicting building users’ satisfaction based on the Weber–Fechner law, where the predicted percentage of dissatisfied users (PD) is determined by means of air enthalpy (h), PD = f(h). The obtained results confirmed the sated thesis. Additionally, the intersection points of the experimental function and isotherms resulting from the Fanger model are presented, where the thermal comfort assessment starts to indicate lower user dissatisfaction results than experimental values. The authors recommend the experimental equation for humid air enthalpies in the range of 50 to 90 kJ/kg. The indoor air quality assessment based on the enthalpy value is simple and can be used to determine the overall Indoor Environmental Quality index of a building (IEQindex).

Changes in EEG signals during the cognitive activity at varying air temperature and relative humidity

In this study, we examined changes in EEG signals during the cognitive activity at different air temperatures and relative humidities (RH). Thirty-two healthy young people acclimatized to the subtropical climate of Changsha, China, were recruited as subjects. They experienced four air temperature levels (26, 30, 33, and 37 °C) and two relative humidity levels (50 and 70%) in a climate chamber. During 175 min-long exposures to each thermal condition, they performed cognitive tasks and their EEG signals were measured. Relative humidity of 70% and increased temperature at this relative humidity significantly increased the relative power of δ-band and significantly decreased relative power of θ-band, α-band, and β-band. This may suggest that subjects were more sleepy but less drowsy, and it was more difficult for them to think clearly. At the same time, subjective evaluations indicated that they could be less alert and it was harder for them to think. However, no changes in performance of tasks measuring cognitive abilities were observed. It remains therefore unclear whether EEG can be a credible marker of changes in cognitive activity as a result of changes in indoor environmental quality in buildings and the future experiments should closely examine this issue.

Multi-Season Assessment of Occupant Responses to Manual Shading and Dynamic Glass in a Workplace Environment

The quality and controllability of the building façade can significantly contribute to building indoor environmental quality (IEQ) as well as the building’s energy efficiency. Advanced technologies that support a façade’s dynamic response to climatic changes, such as electrochromic (dynamic) glazing, have emerged as smart systems for IEQ and environmental sustainability. This research summarizes a four-season study of office workers moving from a floor with conventional blinds to work environments equipped with smart dynamic glazing which changes tint in response to weather condition to control daylighting levels. Multiple occupant environmental satisfaction surveys were conducted over one year to investigate differences in environmental and psychological responses to office settings with manual, and often static, facades as compared to offices with dynamic glazing. This research confirms that dynamic glazing significantly affected occupants’ environmental satisfaction—enhancing individuals’ environmental perceptions and psychological health—as compared to manual blinds. It reveals that the occupants in work environments with dynamic glazing reported 21.7% higher productivity gains, 24.8% increased ability to relax, 12.7% improved concentration, 25.3% better moods and 29.4% greater alertness than when they were in offices in the same building with manual shading devices. Also, the dynamic feature of the smart glazing showed a significant contribution to perceived work productivity while enhancing positive emotional responses by an average of 26%.

The Impact of Environmental Stress on Cognitive Performance: A Systematic Review

OBJECTIVE

In this review, we detail the impact of environmental stress on cognitive and military task performance and highlight any individual characteristics or interventions which may mitigate any negative effect.

BACKGROUND

Military personnel are often deployed in regions markedly different from their own, experiencing hot days, cold nights, and trips both above and below sea level. In spite of these stressors, high-level cognitive and operational performance must be maintained.

METHOD

A systematic review of the electronic databases Medline (PubMed), EMBASE (Scopus), PsycINFO, and Web of Science was conducted from inception up to September 2018. Eligibility criteria included a healthy human cohort, an outcome of cognition or military task performance and assessment of an environmental condition.

RESULTS

The search returned 113,850 records, of which 124 were included in the systematic review. Thirty-one studies examined the impact of heat stress on cognition; 20 of cold stress; 59 of altitude exposure; and 18 of being below sea level.

CONCLUSION

The severity and duration of exposure to the environmental stressor affects the degree to which cognitive performance can be impaired, as does the complexity of the cognitive task and the skill or familiarity of the individual performing the task.

APPLICATION

Strategies to improve cognitive performance in extreme environmental conditions should focus on reducing the magnitude of the physiological and perceptual disturbance caused by the stressor. Strategies may include acclimatization and habituation, being well skilled on the task, and reducing sensations of thermal stress with approaches such as head and neck cooling.

Architectural Indoor Analysis: A Holistic Approach to Understand the Relation of Higher Education Classrooms and Academic Performance

The influence of learning space on users has been broadly accepted and tested. However, the literature has focused on single factor research, instead of holistic approaches. Additionally, lower educational levels have been the focus of interest, while higher education is moving towards multi-method teaching. This paper focuses on how learning spaces for different purposes (practice and lecture rooms) may influence academic performance from a holistic approach of learning physical environment perception. For this, the iPEP scale (Indoor physical environment perception) is used and validated through Cronbach Alpha and Exploratory Factorial Analysis. Then, multiple linear regression is conducted. The results indicate that iPEP measures near to 63 percent of the construct, which is structured in six factors. Moreover, linear regression analyses support previous literature concerning the influence of learning physical environment on academic performance (R2 = 0.154). The differences obtained between practice and lecture room in terms of predictor variables bring to the light the need to diagnose learning environments before designing changes in educational buildings. This research provides a self-reported way to measure indoor environments, as well as evidence concerning the modern university, which desires to combine several teaching methods.

IoT and Big Data Technologies for Monitoring and Processing Real-Time Healthcare Data

Recent advances in pervasive technologies, such as wireless, ad hoc networks, and wearable sensor devices, allow the connection of everyday things to the Internet, commonly denoted as the Internet of Things (IoT). The IoT is seen as an enabler to the development of intelligent and context-aware services and applications. However, handling dynamic and frequent context changes is a difficult task without a real-time event/data acquisition and processing platform. Big data technologies and data analytics have been recently proposed for timely analyzing information (i.e., data, events) streams. The main aim is to make users' life more comfortable according to their locations, current requirements, and ongoing activities. In this article, combining IoT techniques and Big data technologies into a holistic platform for continuous and real-time health-care data monitoring and processing is introduced. Real-testing experiments have been conducted and results are reported to show the usefulness of this platform in a real-case scenario.

Physiological and psychological reactions of sub-tropically acclimatized subjects exposed to different indoor temperatures at a relative humidity of 70

Thermal comfort, self-reported acute health symptoms, cognitive performance, and physiological reactions were examined at four temperatures (26, 30, 33, and 37°C) at a relative humidity of 70%. Thirty-two sub-tropically acclimatized subjects experienced each condition for 175 minute, in balanced order, in a climatic chamber. The perception of heat gradually increased with increasing temperature, but the subjects felt hot only at 37°C. The temperature of 33°C was on average rated as acceptable and only just uncomfortable. The acceptability of air quality decreased linearly with increasing temperature. The intensity of acute health symptoms reported by the subjects increased with increasing temperature, but it was no more than moderate even at the highest temperature; dryness of skin and eye were alleviated. The eardrum temperature, skin temperature and moisture, heart rate, end-tidal carbon dioxide, and weight loss increased significantly with increasing temperature, whereas the percentage of adjacent heart inter-beat intervals differing by >50 ms decreased significantly. These results suggest that the perceived heat, self-reported symptoms, and physiological reactions occurred concurrently. They show additionally that acclimatization to heat may shift the boundary of thermal discomfort to a higher temperature. The role of psychological adaptation and of the contextual aspects of this process still requires clarification in future experiments.

The impact of indoor air temperature on the executive functions of human brain and the physiological responses of body

Background: This study aimed to investigate the effect size (ES) of air temperature on the executive functions of human brain and body physiological responses. Methods: In this empirical study, the participants included 35 male students who were exposed to 4 air temperature conditions of 18°C, 22°C, 26°C and 30°C in 4 separate sessions in an air conditioning chamber. The participants were simultaneously asked to take part in the N-back test. The accuracy, electrocardiogram (ECG) signals and the respiration rate were recorded to determine the effect of air temperature. Results: Compared to moderate air temperatures (22°C), high (30°C) and low (18°C) air temperatures had a much more profound effect on changes in heart beat rate, the accuracy of brain executive functions and the response time to stimuli. There were statistically significant differences in the accuracy by different workload levels and various air temperature conditions(P<0.05). Although the heart beat rate index, the ratio between low frequency and high frequency (LF/HF), and the respiratory rate were more profoundly affected by the higher and lower air temperatures than moderate air temperatures (P<0.05), this effect was not statistically significant, which may be due to significant reduction in the standard deviation of normal-to normal intervals (SNND) and the root of mean squared difference between adjacent normal heart beat (N-N) intervals (RMSSD) (P>0.05). Conclusion: The results confirmed that the unfavorable air temperatures may considerably affect the physiological responses and the cognitive functions among indoor employees.Therefore, providing them with thermal comfort may improve their performance within indoor environments.

Perceived air quality and particulate matter pollution based on field survey data during a winter period

Outdoor air pollution and especially particulate matter pollution is a major environmental health issue that raises concerns of scientists and policy makers. This study focuses on air quality perception in relation to particulate matter in order to find potential patterns. Field questionnaire-based surveys were conducted among pedestrians on two central sites in the city of Athens, Greece, during the winter period while particulate matter of 10 μm or less in diameter (PM₁₀) were concurrently measured on-site at 1-min resolution. The participants were asked to evaluate the dust and the overall pollution-related air quality based on 5-point bipolar scales. Air quality perception patterns were explored considering PM₁₀ concentration, meteorological and thermal conditions, and subjective variables including gender, age, smoking status, and health status. An effect of PM₁₀ on dust perception was identified, suggesting that dusty air quality conditions are reported more frequently when particulate concentration increases. Health status, exposure time, smoking status, and gender were found to affect air quality perception. Participants experiencing health symptoms, exposed to outdoor conditions for more than 30 min, smokers, and females were more likely to report unfavorable air quality conditions. The comparison with the results of a previous study obtained using air pollution station data confirmed the dependence of air quality perception on participants' characteristics and particularly on their health status. Ordinal logistic regression models showed that for pedestrians who were neither smokers nor experiencing health symptoms and were exposed to outdoor conditions for more than 30 min, a PM₁₀ concentration around 64 μg·m^-3 could be a threshold, to perceive dusty air quality conditions.