The excessive heat and humidity in high-geothermal tunnels present significant challenges to personnel safety and structural stability. This study aimed to explore how geological and ventilation parameters influence thermal–humidity control performance of a tunnel during operation. To clarify the influence pathways, a multi-dimensional thermal–humidity environmental assessment framework was established to evaluate six key parameters and quantify their contributions using the Taguchi analysis of variance method. An orthogonal test L27(3 6 ) was designed, incorporating three evaluation indices: the maximum temperature variation in the tunnel ( T D − v ), the heat index ( HI ), and the necessary ventilation duration ( t s ). The results indicate that the surrounding rock temperature exerts the most significant effect on T D − v , with a percentage contribution of 69.32%. The dominant parameter for the HI was found to be the air temperature, accounting for 81.83% of the variation. Regarding the t s index, both air temperature and surrounding rock temperature were identified as critical parameters, with contribution rates of 35.14% and 55.69%, respectively. Considering three indices, the significance of the parameters ranks is as follows: surrounding rock temperature, air temperature, surrounding rock thermal conductivity, ventilation time, fan speed, and relative humidity. The analysis yielded an optimal operational strategy with T D − v (5.35 °C), HI (12.79 °C), and t s (1 day).
Operating room ventilation systems are designed to ensure air cleanliness and reduce the risk of surgical site infections. However, the thermal comfort of surgical staff is often overlooked. The present study investigated whether airflow organisation can reduce thermal disparities amongst surgical team members while maintaining air cleanliness. A typical operating room was modelled using computational fluid dynamics (CFD). Laminar airflow (LAF) and temperature-controlled airflow (TAF) were compared in terms of airflow structure, temperature distribution and the transport of bacteria-carrying particles (BCPs). Thermal sensation was evaluated using the predicted mean vote (PMV) index. The results showed that TAF introduced zonal airflow with differentiated temperature supply, reducing recirculation and stagnation while maintaining effective contaminant removal. Compared with LAF, TAF reduced the surgeon's PMV from 0.83 to 0.30 and narrowed the PMV difference between the surgeon and circulating nurse from 0.72 to 0.17 and between the surgeon and anaesthetist from 1.69 to 1.36. BCP concentrations in the protected zone remained negligible under both systems, while elevated levels in peripheral areas were effectively reduced under TAF. These findings demonstrate that optimised airflow organisation can alleviate thermal demand disparities amongst surgical staff without compromising air cleanliness, offering guidance for the design of operating room ventilation systems.
PM 2.5 has become a major pollutant in the atmospheric environment, posing a serious threat to people's health and seriously hindering the sustainable development of urban environments. However, there is still limited assessment of the health risks and economic losses associated with PM 2.5 pollution in megacities. Therefore, this study systematically analysed the spatiotemporal distribution characteristics, health risks and economic losses associated with PM 2.5 concentrations in seven typical Chinese cities. The results show a typical ‘bimodal’ structure with fluctuations up to 10–12 μg/m 3 throughout the day in the northern cities. Fluctuations are only 2–3 μg/m 3 throughout the day in southern cities. Seasonal differences in PM 2.5 concentrations are regular, showing an overall trend of winter > spring > autumn > summer. The distribution of PM 2.5 concentrations in different cities shows that PM 2.5 tends to accumulate in areas with high population density, high traffic density, high energy consumption and high heating emissions. PM 2.5 pollution causes an average of more than 50 premature deaths per million people per year in different cities. In addition, economic losses due to PM 2.5 pollution average more than 1.28 × 10 6 per year. PM 2.5 is inversely proportional to temperature and humidity concentrations, and has a significant positive correlation relationship with PM 10 , SO 2 , CO and NO 2 .
Creating personalized indoor environments has become a key focus in academic research due to its crucial role in promoting human well-being, supporting energy conservation and improving building performance. This study explored how thermal perception varies across four typical interior styles: traditional Chinese, classical European, industrial and modern minimalist, using virtual reality (VR) to control visual variables. Experiments were conducted at 18 °C, 24 °C and 30 °C. Two-way analysis of variance revealed that while temperature was the primary factor affecting thermal comfort (η 2 = 0.454, p < 0.001), scene type also had a notable effect (η 2 = 0.035, p = 0.014), particularly under moderate and warm conditions (η 2 = 0.085, p = 0.001). In addition, the study found that the thermal environment had a significant effect on skin temperature, heart rate and blood pressure indicators, while the visual environment had no significant effect. The innovative contribution of this research lies in systematically demonstrating the interactive effects of visual scene styles and thermal environments in indoor settings by integrating VR-based experimental design with physiological and subjective measures. This suggests that enhancing the visual environment can improve perceived thermal comfort and support energy-efficient indoor design.
The extensive application of electrosurgical devices enhances surgical efficiency while generating considerable surgical smoke, posing health hazards to medical staff and patients. Current local exhaust systems show limited performance in mitigating operating room smoke pollution. This study employed simulation methods to investigate the influence of exhaust velocity and the position of the suction port on the removal efficiency of surgical smoke. Results showed that increasing exhaust velocity improved exhaust volume and significantly reduced indoor particle concentrations. With a specific exhaust system, at an exhaust velocity of 5 m/s, an exhaust efficiency as high as 99.64% was achieved. The concentration can be reduced to 1.173 × 10 7 particles/m 3 , whereas the concentration in the breathing zone can be minimised to 4.492 × 10 6 particles/m 3 . This concentration is significantly lower than the concentration of 10 9 particles/m 3 observed without exhaust devices, thereby effectively reducing the exposure risk for medical staff. Increasing the horizontal or vertical distance between the suction port and the incision significantly decreased exhaust efficiency. The relative position must be strictly controlled (within 2 cm horizontally and vertically) to ensure effective smoke removal. In addition, both the increase in suction port diameter and the adoption of the bell-mouth configuration may deteriorate the smoke removal efficiency.
Background: Indoor environmental quality (IEQ) significantly influences occupant stress in office settings, yet the combined effects of multiple environmental stressors, moderated by personal characteristics, remain underexplored. Objective: This study examines the interaction effects of air temperature, lighting correlated colour temperature (CCT), and background noise on stress responses among office workers, with attention to individual differences in gender and body mass index (BMI). Methods: A mixed-design controlled experiment was conducted with 52 young adults in an open-plan office within a North American Mediterranean climate, varying temperature (20 °C vs. 25 °C), CCT (2700 K vs. 6500 K), and noise level (50 dB vs. 65 dB). Stress was assessed using physiological and psychological indicators. Key Results: Stress responses were shaped not by individual environmental attributes in isolation, but through complex interactions among temperature, CCT, and noise, further moderated by BMI and gender. Individuals with overweight/obese BMI showed heightened sensitivity to warm temperatures, cool CCT, and high noise, while males exhibited greater sympathetic activation under warm and noisy conditions compared to females. Implications: These findings underscore that a one-size-fits-all approach to office environmental design is insufficient. Accounting for occupant heterogeneity, particularly BMI and gender, is essential for developing personalized IEQ strategies that promote workplace well-being.
Based on a validated numerical model with a prediction error of <5%, this study investigated the condensation characteristics of a radiant cooling ceiling integrated with a wall-attached jet through transient computational fluid dynamics simulations. Research indicates that the areas comprising 25% of the radiant cooling ceiling near the outlet side were identified as high-risk condensation areas. On this basis, numerical calculations were conducted to investigate the effects of jet velocity, jet temperature, and initial indoor temperature on condensation risk, the indoor thermal environment, and the time required to achieve a comfortable environment. For every 0.2 m/s increase in jet velocity, the minimum temperature in this area rises by 0.49 °C, shortening the time to achieve thermal comfort by 105 s. At a jet velocity of 1.6 m/s, the minimum temperature remains over 1 °C above the dew point, eliminating condensation risk. At this velocity, every 2 °C decrease in jet temperature reduces the comfort attainment time by 120 s, while every 1 °C increase in initial indoor temperature extends it by 90 s. The recommended parameters are 1.6 m/s and 22C, effectively meeting cooling demands, ensuring thermal comfort, and reducing energy consumption.
With the aging population, the design of care homes has gained increasing attention. However, the older adults’ preferences for various environmental attributes were often overlooked and still need to be further explored. This study aims to explore these environmental preferences to support their emotional well-being. A fractional factorial design was adopted to identify significant factors. Totally, 32 scenes were developed, incorporating eight environmental attributes: illuminance, colour temperature, view out, floor texture, colour contrast, visual complexity, layout, and style, with each attribute examined at two types. In total, 111 valid electroencephalogram (EEG), questionnaires, and interview data were collected from 37 older adult participants. The environmental preferences of older people were evaluated using independent samples t -tests, linear regression, interaction effect analysis, and EEG topographic mapping. The results from EEG data further enriched environmental preferences by capturing older adults’ subtle emotional responses. This study identified the preferred types of environmental attributes among older people, contributing to the construction of an emotionally supportive environment and promoting older adults’ psychological well-being.
Growing numbers of lowlanders are travelling to high altitudes for occupational and recreational purposes. Hypoxia constitutes the principal physiological challenge at high altitudes, causing notable discomfort and potential life-threatening conditions. This study systematically analysed three key physiological systems during short-term high-altitude exposure and identified the most clinically relevant indicators for these systems. Six Acute Mountain Sickness (AMS) scales were summarized from a subjective monitoring perspective. Three hypoxia alleviation methods with practical implementation guidelines are presented. Based on identified limitations in current evaluation and intervention methods, we propose future research directions to improve safety protocols for high-altitude visitors and to optimize acclimatization strategies. Highlights The relevant indicators for three key physiological systems were selected. The key symptoms of six AMS questionnaires were analysed. Three methods of alleviating hypoxia are summarized. Development of an oxygen comfort assessment method is essential for mild AMS. Thermal-oxygen coupled environment control technology is prospective.
The psychological and physiological health of astronauts in microgravity is influenced by multiple factors, amongst which light and colour design has a crucial role in alleviating stress and optimizing overall habitability. However, current lighting and colour optimization strategies in space stations lack spatial differentiation, rely on subjective and fragmented evaluation methods, and are limited by unclear regulatory mechanisms. These issues hinder progress in optimizing space environments. This study reviewed the psychological and physiological effects of long-term spaceflight and the regulatory impact of light and colour on the human body. Based on the current state of space station designs and the hierarchy of human needs, functional requirements and zoning were clarified. A comprehensive examination of light and colour schemes has highlighted how optimized design can improve habitability in microgravity. Furthermore, the indicators and corresponding methodologies for evaluating environmental influences on humans was summarized, and a multi-level, interdisciplinary framework for optimizing future space station lighting and colour design has been proposed. Future research should systematically explore the effects of different schemes using, subjective, physiological, task performance and quantitative analyses, based on psychology, medicine and related fields. Human factors and environmental-design-integrated feedback were assessed to scientifically guide improvement in space station light and colour habitability.
During the COVID-19 pandemic, the high-density and enclosed environments of rail transit systems have increased respiratory transmission risk, emphasizing the need to investigate droplet dispersion mechanisms and influencing factors in rail carriages. This article reviews the numerical simulation and experimental studies on respiratory droplet transmission in rail vehicles since 2020, focusing on droplet characteristics, infection risk assessment and influencing factors in dense and narrow environments. The review encompassed high-speed trains, conventional trains and subways, analysing the effects of ventilation, passenger behaviour and environmental conditions on spread of droplet. Through systematic literature search and keyword co-occurrence analysis, 27 core studies were identified. The results indicated that numerical modelling mostly employed Eulerian and Lagrangian frameworks with various turbulence models, simplifying 3D carriage geometries with seats and occupants. Key boundary conditions included mixed and new type ventilation systems and idealized human exhalation. These models simulated spherical droplets from coughing and breathing under velocities of 0.1–20 m/s. Experiments are more complex and time-consuming but can provide realistic insights. For infection risk assessment, optimizing models for special environments is essential. Advanced ventilation modes and higher ventilation rates are effective for controlling droplet transmission, while passenger behaviours could significantly affect dispersion and would require further research.
Indoor environmental quality (IEQ) profoundly impacts residents’ health and well-being, with poor IEQ linked to various health risks. The study examines IEQ and its health implications for residents in rural and semi-urban areas of eastern India and was conducted across four coastal blocks in South 24 Parganas, West Bengal. The study involved 1332 participants. It explored the impact of climate, environmental conditions and building features on health throughout different seasons. Essential factors such as thermal, visual and acoustic comfort and productivity were crucial to residents’ satisfaction and overall well-being. A strong correlation emerged between building design, residents’ perceived quality and satisfaction, emphasising the need for thoughtful design approaches. ANOVA results showed significant IEQ differences across communities and genders. Serious health issues have been linked to poor IEQ, including vestibular neuritis, dermatological disorders and dyspnoea – symptoms often associated with sick-building syndrome (SBS). Principal component analysis (PCA) revealed three components accounting for 59.2% of SBS cases. Additionally, integrating the Universal Thermal Climate Index provided more profound insights into heat stress prevalence, offering a unique perspective on environmental challenges. The findings underscore the importance of bioclimatic design strategies tailored to the specific needs of coastal and rural settings in eastern India.
Global warming is increasing the frequency and intensity of heat exposure experienced by people working in hot environments, thereby posing a threat to human attention. However, existing attention-evaluation techniques are often susceptible to environmental influences. To address this issue, a multi-dimensional framework based on human subjective perception was proposed. Fourteen participants were recruited to perform a 30-min continuous performance test under indoor temperatures of 30°C, 33°C and 36°C. During the task, emotion, sleepiness and perceived workload data were collected, and the performance index (PI) was calculated. Thereafter, a generalized linear mixed model (GLMM) was used to develop an exploratory model of attention. Results showed that PI decreased significantly with increasing indoor temperature ( p < 0.05). Although overall emotion, sleepiness and perceived workload varied across temperature conditions, no statistically significant differences were observed ( p > 0.05). However, the GLMM analysis revealed that sleepiness ( p = 0.025), positive emotion ( p < 0.001), mental demand ( p = 0.023), physical demand ( p < 0.001) and frustration ( p = 0.001) were significantly associated with PI. Based on these variables, a multi-dimensional exploratory model of attention was established ( F = 6.775, p < 0.001). The findings provide a theoretical basis for evaluating human attention under heat exposure.
Climate change is fundamentally reshaping environmental health risks in cities worldwide. Heat and air pollution are increasingly coupled, creating compound exposures whose health impacts exceed those of individual stressors. These coupled conditions have shifted health risks towards the upper tail of the distribution, producing sharp increases in short-term mortality and acute morbidity that are often overlooked by assessments centered on average exposures. Such tail risks for environmental health are unevenly distributed across populations and urban settings, reflecting structural inequalities in vulnerability, environmental exposure and adaptive capacity. Conventional frameworks that treat heat and air pollution independently are therefore insufficient for capturing the full scope of climate-sensitive health burdens. Addressing these emerging risks requires a reframing of health risk perception, greater emphasis on extreme events and compound exposures, and more integrated public health and urban governance approaches. Recognizing and characterizing upper tail risks for health is essential for improving preparedness, reducing inequalities and safeguarding public wellbeing under a warming climate.
University classrooms and meeting spaces have been regarded as crucial to the research on how interior spatial features could influence students’ emotional experiences. This study examined how colour, material and transparency, alone and in combination, could shape students’ affective responses in university classrooms and meeting rooms. This objective was achieved by constructing a virtual reality (VR) experimental platform and through physiological signal measurements, photoplethysmography (PPG) and electrodermal activity (EDA). Furthermore, a three-process experimental design (immersive environments, multimodal assessment and data processing) and analysis of variance (ANOVA) were introduced. These were used to systematically compare the interaction effects of various variable combinations on emotional indicators such as pleasure, arousal and dominance (PAD). The findings showed that colour, material and transparency interact with each other to a significant extent. Notably, positive emotional experiences were significantly enhanced by various combinations such as “orange colour + metal material”, whereas negative emotions and psychological tension were possibly evoked by “blue colour + metal material”. On this basis, it was concluded that the integration of multiple factors in university teaching and communication interior spaces is essential for optimized emotional regulation.
Heatwaves can usually lead to severe attentional decline. However, the effect of heatwaves has not been sufficiently evaluated quantitatively, particularly through some easily acquired thermoregulation-related indices. To address this issue, 14 participants were exposed to various temperatures of 22 degrees C, 31 degrees C, 33 degrees C and 35 degrees C, under 55% relative humidity, over a 150-min duration. The air temperature of 22 degrees C was used as a control condition. Four attentional tasks were administered at each environmental temperature. During the experiment, mean skin temperature (MST), core temperature, heart rate (HR) and cortisol were measured. Results showed that the attentional performance was reduced under 31 degrees C, 33 degrees C and 35 degrees C (p < 0.05). The mean HR was reduced over the exposure time under all temperatures (p < 0.001) but rose significantly with air temperature (p < 0.05). Meanwhile, MST was increased significantly by the air temperature (p < 0.001) under 31 degrees C, 33 degrees C and 35 degrees C, over the exposure duration. However, MST was reduced significantly over the exposure time under 22 degrees C (p < 0.05). Furthermore, cortisol concentration varied significantly with air temperature (p < 0.05). Correlation analysis indicated that the attentional performance was negatively correlated with MST, with a Spearman's rho of -0.58 (p < 0.05), based on which, a quantitative relationship for the evaluation of attention was proposed using R-2 of 0.69 (p < 0.05).
Air-conditioned mosques, which have large volumes and are used intermittently five times daily, face significant energy consumption challenges. This study investigated air-conditioning (AC) operation and ventilation strategies in a typical large-scale air-conditioned mosque in the hot-humid climate of Malaysia. Simulations were conducted to evaluate the impact of various AC operational scenarios and ventilation strategies on energy efficiency and thermal comfort. The findings emphasize that strategic modifications can yield significant energy savings without compromising worshipers' comfort. A pre-cooling period of 10 min before prayers, except for dawn prayers, which require 20 min, demonstrates a 5% reduction in energy consumption. In an advanced scenario that integrates natural ventilation of lower (doors) and upper (clerestory windows) openings during dawn prayers, a 10-min pre-cooling period for other prayers, and an optimized adaptive setpoint temperature, energy savings of up to 15% can be achieved. Thermal comfort analysis shows that the mosque maintains thermal comfort during dawn prayer ventilation, with the upper opening, at an indoor temperature of 26-27 degrees C and an air exchange rate of 3 h-1. The results highlight the need to maintain indoor temperatures within optimal ranges to enhance occupant comfort while minimizing energy demand. This study has underscored the importance of integrating passive and active cooling strategies to improve energy efficiency in religious buildings with intermittent occupancy patterns.
