High Indoor Temperatures Research Articles

Subjective evaluation of thermal comfort of tropically acclimatized subjects in air conditioned, naturally ventilated and radiant cooling environments

The thermal sensation of people is subjective. It depends on the external climatic condition and thermal history of a person. Thermal comfort standards suggest a narrow temperature range to assert an environment as comfortable or otherwise. It is important to evaluate people’s thermal perception in different climatic regions and set comfort limits based on their thermal perception. This study evaluates the thermal perception of subjects in hot and humid climatic regions at higher indoor temperatures and air velocities. Three different thermal environments chosen for the study are air conditioned (AC), naturally ventilated (NV), and radiant cooling (RC) thermal environments. The study shows that more than 80% of subjects voted as comfortable in AC and RC thermal environments for the measured Top and va range of 25.3 – 28.4℃/0.1 – 0.3m/s and 25.9 – 29.1℃/0.1 – 0.9m/s respectively. The findings gathered from the study in NV environment indicate that 68% of subjects opt for the use of table fans over ceiling fans. The subjects' free control of air movement improves their thermal sensation over no control of air movement, indicating that they prefer table fans and free control of air movement. In AC, NV, and RC thermal environments, humidity and air quality remain uncontrolled. In AC and RC thermal environments, less than 20% of subjects voted unacceptable for the humidity sensation and Perceived air quality (PAQ) scales in nearly all the studied experimental conditions. In NV thermal environment, the percentage of subjects voting dissatisfied on the humidity sensation scale and PAQ scale is 30-52% and 26-37%, respectively. This outcome shows that a thermally comfortable environment with air movement improves subjects' humidity sensation and PAQ even when humidity and air quality are unaltered. The study points out that air velocity played a vital role in influencing the thermal sensation, humidity sensation and perceived air quality of subjects in the three studied thermal environments. Further the study shows that with free control of air movement will significantly aid in rising the comfort temperature band of tropically acclimatized subjects. Practical application The study shows the variation in limits of thermal comfort indices such as operative temperature and air velocity for tropically acclimatized subjects in three thermal environments. The same group of subjects participated in the subject study conducted in air conditioned, naturally ventilated and radiant cooling thermal environments. The outcomes indicate that subjects are comfortable at higher indoor temperature and air velocity. Further the outcomes showed that the humidity and air quality sensation of subjects is influenced by the subjects’ thermal sensation and air velocity.

The effect of structural retrofitting and ventilation scenarios on the indoor microclimate of a historical library: The Necip Pasa Library, Turkiye

Structural retrofitting in buildings may result in changes in the indoor microclimate. Chemical, mechanical and biological deterioration can be seen in the cultural properties as a consequence of substrates and inappropriate microclimatic conditions such as high indoor temperature, relative humidity and fluctuations of them. The primary aim of the study is to evaluate the effect of the structural retrofitting, that the building underwent, on the chemical degradation risk of the library collection based on two different ventilation scenarios. One is natural ventilation which is an existing situation since the building is free-floating. The other one implementing a mechanical ventilation system into the building. To be able to compare the microclimate that affects the library collection pre- and post-retrofitting, two models are developed in DesginBuilder and simulated for both scenarios. According to the results of the post-retrofitting model, mechanical ventilation reduced the risk of chemical degradation by 38 %, while natural ventilation did not cause any effect. Natural ventilation gives a similar output in the pre-retrofitting model as in the post-retrofitting model. Mechanical ventilation in the pre-retrofitting model achieves a 33 % reduction in chemical degradation risk. Structural retrofitting only achieves a 1 % reduction in the chemical risk level for both ventilation scenarios. Thus, its effect on the indoor microclimate is insignificant. This study shows that creating simulation models effectively assesses potential risks pre-post-structural retrofitting or any retrofitting in historical buildings. Simulations reveal that mechanical ventilation is a better choice for decreasing chemical degradation risks for the library.

Investigations on an integrated air-conditioning system using technologies of desiccant dehumidification, indirect evaporative cooling and CO2 capture

The advance of air-conditioning systems has become a popular topic, due to its huge energy consumption and the increasing demand of improving indoor air quality. Although various approaches have been proposed for humidity, temperature and CO2 control, their coordination has not yet been studied. In this study, the technologies of desiccant dehumidification, indirect evaporative cooling and direct CO2 capture are innovatively integrated in an air-conditioning system, by which their respective advantages can be exerted and limitations can be compensated. Under a base working condition with ambient temperature of 35 °C and relative humidity of 80%, the overall coefficient of performance of the integrated system reaches 0.93, with an improvement of 53.3% against a conventional scheme. The integrated system is more efficient at higher crowdedness. With occupant number from 2 to 22 in a room, the advantage of the integrated system ranges from 50.7% to 85.6%. Parametric studies on different indoor and outdoor conditions are conducted, indicating that the energy efficiency advantage is more outstanding at higher indoor temperature, lower ambient temperature and lower ambient humidity. The factors of economic, environment and health are discussed, where the integrated system exhibits superiority against conventional systems and existing studies as well. Approaches are raised to improve the performance and promote future studies. The results in this paper contribute to providing a scheme for the integration of different technologies and enlightening insights for the advance of air-conditioning systems for the sake of air quality improvement, energy saving and emission reduction.

Sustainable construction materials for low-cost housing: Thermal insulation potential of expanded SBR composites with leather waste

In recent years, there has been a growing interest in improving energy efficiency and thermal comfort in low-income housing, especially in regions prone to extreme climatic conditions. Conventional construction materials such as bricks and concrete exhibit shortcomings in energy efficiency, resulting in high indoor temperatures. This scenario not only impacts residents' well-being but also increases energy consumption, especially for air conditioning systems, potentially straining the electrical infrastructure in hot climate areas, leading to power outages and adverse consequences for the community and local industry. This study proposes an innovative and sustainable solution: the use of expanded styrene-butadiene rubber (SBR) with micronized leather shavings, possessing thermal insulation properties. The thermal insulation capacity of the composites was evaluated using heat flow methods, hot/cold plate heat flow analysis, and impedance tube acoustic method. The SBR/Leather waste composite at 20 phr emerges as a viable, promising, and sustainable alternative, exhibiting significant thermal insulation capacity with a thermal conductivity of 0.073 Wm-1.K−1 and temperature attenuation close to 15 °C, potentially enhancing comfort and quality of life in urban areas. The thermal insulation results of the other composites also surpassed traditional construction materials such as building boards, plywood, fiberglass, asphalt roofing, and cement tiles. The study demonstrates the feasibility of reusing leather as a reinforcing filler in rubber-based foams to produce thermal insulation materials, offering a sustainable solution to mitigate urban heating and improve quality of life in cities.

Investigating student perceptions and vulnerability to heat stress in campus residences using Reddit: Climate change, health, and wellbeing

AbstractThis exploratory research investigated the sufficiency of existing infrastructure to adapt to high temperatures and explored the perceptions of heat stress from students in on‐campus residences at the U15 Group of Universities in Canada. The prevalence of air conditioning in student residences was used to estimate the adaptive capacity of existing infrastructure, and posts and comments on Reddit relevant to the perceptions of heat stress were collected in January 2023 through a query of relevant key words within each institution's subreddit. Most institutions (80%) had some residences with air conditioning. However, four main themes emerged through the thematic analysis of 409 posts and comments on Reddit: (1) complaints, (2) impacts on wellbeing, (3) adaptation strategies, and (4) climate change. The perceptions of heat stress from students suggest that existing available cooling strategies do not provide sufficient adaptation to high indoor temperatures. Recognizing student perceptions and experiences is necessary in designing and implementing future adaptation strategies to promote the health and wellbeing of postsecondary students in Canada.

Indoor Temperature and Energy Insecurity: Implications for Prenatal Health Disparities in Extreme Heat Events.

Extreme heat events are a major public health concern and are only expected to increase in intensity and severity as climate change continues to accelerate. Pregnant people are physiologically more vulnerable to the effects of extreme heat, and exposure can induce harm on both the pregnant person and the fetus. This commentary argues that there is a need for greater epidemiological research on indoor heat exposure and energy insecurity as potential drivers of maternal and child environmental health disparities. While there is substantial evidence linking ambient (outdoor) high temperature to pregnancy-related outcomes, there is a lack of epidemiological evidence to date on pregnant people's exposure to high indoor temperature and adverse maternal and/or child health outcomes. Energy insecurity is disproportionately experienced by people with low incomes and/or people of color, and indoor temperature may play a role in shaping socioeconomic and racial/ethnic disparities in maternal and child health in the United States. Further research is needed to understand the relationship between indoor heat exposure, energy insecurity, and pregnancy outcomes in both parents and children and to inform potential policies and practices to enhance resilience and reduce maternal/child health disparities. https://doi.org/10.1289/EHP13706.

Sensing the impact of extreme heat on physical activity and sleep.

This study assesses the person-specific impact of extreme heat on low-income households using wearable sensors. The focus is on the intensive and longitudinal assessment of physical activity and sleep with the rising person-specific ambient temperature. This study recruited 30 participants in a low-income and predominantly Black community in Houston, Texas in August and September of 2022. Each participant wore on his/her wrist an accelerometer that recorded person-specific ambient temperature, sedentary behavior, physical activity intensity (low and moderate to vigorous), and sleep efficiency 24 h over 14 days. Mixed effects models were used to analyze associations among physical activity, sleep, and person-specific ambient temperature. The main findings include increased sedentary time, sleep impairment with the rise of person-level ambient temperature, and the mitigating role of AC. Extreme heat negatively affects physical activity and sleep. The negative consequences are especially critical for those with limited use of AC in lower-income neighborhoods of color. Staying home with a high indoor temperature during hot days can lead to various adverse health outcomes including accelerated cognitive decline, higher cancer risk, and social isolation.

Impact of outdoor heat adaptation on indoor thermal conditions – Combining microscale urban climate and building performance simulation

To what extent can outdoor heat adaptation measures in urban districts help to reduce high indoor temperatures in buildings and thus enhance indoor thermal conditions? To answer this question microscale meteorological simulation (MMS) and building performance simulation (BPS) are combined in a model chain approach. Two existing residential German districts with different urban designs are modelled in the MMS tool ENVI-met. For both districts, a representative residential building (one from the Wilhelminian period and one large panel construction type) is modelled using the BPS tool IDA-ICE. Different scenarios of heat adaptation measures are applied to analyse how changes in urban and building design (e.g. white (cool) roofs (high albedo), white traffic areas (high albedo), intensive green roofs, urban trees, facade insulation or facade greening) affect outdoor and indoor temperatures. The MMS results highlight that the district from the Wilhelminian period is less heat resilient and that the efficacy of heat adaptation measures on heat reduction in open space depends on the urban design and the daytime. Regarding the efficacy of heat adaptation measures on indoor thermal conditions, our findings indicate that the larger share of the indoor cooling effect is not caused by the outdoor air temperature reduction by the outdoor heat adaptation measures but by the change of the building physics in the BPS model (e.g. changing the surface reflectance of the white roofs). White roofs and intensive green roofs show the largest cooling effect by reducing the operative room temperature by more than 1 Kelvin. Our findings also demonstrate that facade insulation can act as both, climate adaptation and mitigation measures.

A Comprehensive Assessment of Indoor Air Quality and Thermal Comfort in Educational Buildings in the Mediterranean Climate

Maintaining good indoor air quality and thermal comfort is a challenge for naturally ventilated educational buildings, as it can be difficult to achieve both aspects simultaneously. Nonetheless, most of the existing studies only focus on one aspect. To explore the potential of balancing indoor air quality and thermal comfort, both topics must be investigated concurrently. This study assessed indoor air quality and thermal comfort in 32 naturally ventilated classrooms of 16 primary and secondary schools in the Mediterranean climate, based on a large on-site measurement campaign lasting one year that gathered over 460 hours of data. The research investigated occupants’ adaptive behaviors, analyzed the actual thermal comfort of around 600 students, and characterized the representative scenarios leading to good and poor indoor air quality and thermal comfort by clustering analysis. The results showed that poor indoor air quality was mainly due to closing windows and doors in winter, while thermal discomfort mainly occurred in summer because of the high indoor temperature. The findings suggested that a proper ventilation protocol is the key to balancing indoor air quality and thermal comfort.

Cumulative Multi-Day Effect of Ambient Temperature on Thermal Behaviour of Buildings with Different Thermal Masses

In most studies, the effect of the thermal capacity of the building envelope on changes in internal temperatures is reduced to a 24 h period. During this period, daytime heat gains are balanced by nighttime heat losses. The maximum indoor temperature, the diurnal variation of the indoor temperature and the time lag between the occurrence of the maximum daily temperature determine the effect achieved. The aim of the article was to show that the effect of the thermal capacity of a building on the indoor temperature is not limited to 24 h but accumulates over a period of several days, mainly depending on the temperature and solar radiation history of the previous days. As a result, contrary to what some studies have suggested, the bedrooms of heavier buildings remained significantly colder at night during periods of prolonged high outdoor temperatures. The results obtained may fundamentally influence the perception of the effect of using the high thermal capacity of the building envelope to reduce high indoor temperatures in hot weather.

Investigation of Indoor Thermal Environment and Heat-Using Behavior for Heat-Metering Households in Northern China

Heat-using behavior has a major impact on heating energy in heat-metering systems, and therefore, a better understanding can assist in behavior guidance to reduce energy. The objective of this paper was to investigate heat-using behavior, including adjusting heating end valves and operating windows, and identify the main factors affecting the heat-using behavior of households in heat-metering modes. Thirty households were measured and surveyed. The factors influencing heat-using behavior, including outdoor and indoor environmental parameters and time of day, were analyzed. The results are the following: (1) The indoor temperature for heat-metering households was relatively high, up to 24–25 °C (95% confidence interval). (2) The heat-using behavior of households has a lack of rationality: a low proportion of households with adjusted heating end valves, high indoor temperature settings, and more frequent window openings. Improving indoor comfort is the main reason for households to adjust heating end valves, accounting for 79% (95% confidence interval, CI: 71–87%). “Thermostat control valve does not work” is the main reason for households without adjustment, accounting for 63% (95% confidence interval, CI: 53–72%). (3) Time of day and indoor temperature affect active households’ willingness to adjust heating end valves. Time of day, indoor temperature, and outdoor temperature have impacts on opening windows during heating periods.

TOWARDS ACHIEVING SUSTAINABLE DEVELOPMENT GOAL-2030 AGENDA-THIRTEEN: SELECTIVE TREATMENT OF SUN-FACING RESIDENTIAL WINDOW FABRICS IN THE TROPICAL BUILDING DESIGN

High solar gains associated with the Tropical climate result in high indoor temperature, the consequence of which induces indoor thermal discomfort. Particularly, both the East and West facing component building envelope receive more solar gains through early morning sun rise and late afternoon sun set respectively, thereby raising the indoor temperature of the affected spaces within the periods. However, the need to optimize indoor thermal comfort through mechanical installations among others, increases carbon emissions into the atmosphere, as buildings account for about 40% of global emissions through their construction, operation and maintenance. Due to its importance at the global level, Climate Change induced mitigation has resulted into promulgation of seventeen-pronged (17) United Nation’s Sustainable Development Goal 2030 (SDG-2030) Agenda. Of particular relevance within the precinct of built environment is the Agenda thirteen (Agenda-13) which encompasses the need for urgent action to combat Climate Change and its impacts across various areas of human engagements. It is on this basis that this research work explored beneficial impacts of selective treatment of East and West-facing residential building window fabrics, in the tropical city of Ogbomoso, Nigeria. In its approach, comparative evaluations of indoor solar gains using single-glazed and double-glazed virtual building models was carried out through DesignBuilder based simulations. The results indicate 8.5%, 8.5% and 8.6% annual reductions in the indoor solar gains in the whole building, East-end apartment and West-end apartment respectively, with the adoption of the double-glazed windows. Focusing specific individual sun-facing functional spaces (bedrooms in this case), more significant reduction in the indoor solar gains (i.e., about 28%) was recorded in each case. This research output may influence subsequent design and composition of the sun-facing window fabrics at this local level, thereby leading to reduced mechanical installations, for optimum indoor thermal comfort. This is an attempt to contribute towards achieving SDG-2030 Agenda-13 individually at this level, for overall collective realization at the global level. This endeavour aims at reducing carbon emissions at the building micro level in the study area, for overall clean, safe and sustainable global environment. This submission is part of an ongoing research work scheduled to be validated with life prototype/physical models subsequently.

Optimum thermal performance of green walls systems and design requirements against heat transfer of conventional external walls of low-rise concrete buildings in hot regions

This paper presents a study on how the thermal performance of conventional external walls of concrete building could be improved against heat transfer in hot regions. 45 buildings were visited to observe the heat transfer from the warmer side of the external wall to the cooler side. The measurements showed that the conventional walls are insufficient because of high indoor temperatures. This study introduced three environmentally friendly scenarios to enhance the efficiency of the concrete wall against heat transfer. In the first scenario, a continuous air layer was added at the middle of the wall to form an aired-concrete wall. In the second scenario, a living green layer was added on the exterior side of the wall to form a living-concrete wall. The third scenario merged the previous two insights to form a living-aired-concrete wall. Thermal models were prepared to conduct thermal analysis. The results showed that the air layer deactivates the work of thermal bridges and improves the thermal resistance of the wall 5 to 15 times. In the aired-concrete wall, the results showed that the minimum depth of the air layer should be at least 6 cm, to secure a convenient indoor environment with indoor temperature not more than 25 °C. Furthermore, the results showed that adding only an outdoor living green layer to the conventional wall is insufficient in all thermal zones of hot regions. Finally, the best thermal performance against heat transfer was found in the living-aired-concrete wall using outdoor Perennials plants and 5 cm middle air layer.

Dynamic modeling and data fitting of climatic and environmental factors and people's behavior factors on hand, foot, and mouth disease (HFMD) in Shanghai, China

BackgroundHand, foot, and mouth disease (HFMD) appear to be a multi-wave outbreak with unknown mechanisms. We investigate the effects of climatic and environmental factors and changes in people's behavior factors that may be caused by external factors: temperature, relative humidity, and school opening and closing. MethodsDistributed lag nonlinear model (DLNM) and dynamic model are used to research multi-wave outbreaks of HFMD. Climatic and environmental factors impact on transmission rate β(t) is modeled through DLNM and then substituted into this relationship to establish the dynamic model with reported case data to test for validity. ResultsRelative risk (RR) of HFMD infection increases with increasing temperature. The RR of infection first increases and then decreases with the increase of relative humidity. For the model fitting HFMD dynamic, time average basic reproduction number [R0] of Stage I (without vaccine) and Stage II (with EV71 vaccine) are 1.9362 and 1.5478, respectively. Temperature has the highest explanatory power, followed by school opening and closing, and relative humidity. ConclusionWe obtain three conclusions about the prevention and control of HFMD. 1) According to the temperature, relative humidity and school start time, the outbreak peak of HFMD should be warned and targeted prevention and control measures should be taken. 2) Reduce high indoor temperature when more than 31.5 oC, and increase low relative humidity when less than 77.5% by opening the window for ventilation, adding houseplants, using air conditioners and humidifiers, reducing the incidence of HFMD and the number of infections. 3) The risk of HFMD transmission during winter vacations is higher than during summer vacations. It is necessary to strengthen the publicity of HFMD prevention knowledge before winter vacations and strengthen the disinfection control measures during winter vacations in children's hospitals, school classrooms, and other places where children gather to reduce the frequency of staff turnover during winter vacations.

Experimental study of the thermal behavior of PCM and heavy building envelope structures during summer in a temperate climate

The main objective of the study was to evaluate the effects of PCM and traditional masonry construction on the summer thermal performance of the non-air-conditioned residential building in a temperate climate. The research was conducted in three rooms. In the first case, the lightweight frame construction of the walls and ceiling was covered with gypsum board on the inside, while in the second, a layer of Rubitherm® RT25HC was placed. The third room used masonry walls and a reinforced concrete roof. All rooms had identical flooring. The study was conducted between 13.08 and 18.09.2020. For the night period, various rates of mechanical ventilation were used to maintain the room temperature within the range of optimal PCM melting temperatures. The results of the study indicate significantly higher effectiveness of traditional high thermal capacity building materials than PCMs for lowering high indoor temperatures in summer. This occurs when there is a marked increase in outdoor temperature on at least one day, while at the same time the indoor temperature does not significantly exceed the PCM's melting temperature range specified by the manufacturer. Studies have further shown that the cooling efficiency of PCMs remains at a reasonably high level only for a small number of days in summer. This occurs when there is a marked increase in outdoor temperature on at least one day, while at the same time the indoor temperature does not significantly exceed the PCM's melting temperature range specified by the manufacturer.

Computational modelling in a high rise building with different building envelope materials for sustainable living

This research focuses on identifying a sustainable material for building envelope for energy efficacy in naturally ventilated high rise residential buildings through CFD. Convective heat transfer is observed in three levels of the 14 storied highrise naturally ventilated building using three different building envelope materials ? burnt clay bricks, solid concrete block, and hollow concrete block. To artificially create the environment with CFD the different temperatures and velocities are used. The boundary conditions - initial outdoor temperatures 30 ?C and 23 ?C, respectively, were kept constant and the initial outdoor velocities 1 m/s to 10 m/s, were varied and simulated at 12 noon condition. Simulation results reveal, higher indoor temperatures in the roof exposed floor. At 30?C it is observed that there is a 0.2-0.3?C temperature difference between the burnt clay brick wall and the hollow concrete block wall through the varied velocities. In all cases of air velocities, the air temperature in the indoor spaces of the solid concrete block wall was found to be highest. This proves that solid concrete block wall has the highest conductivity and least resistivity over the other two materials. In the hollow concrete block, the process of conduction is slow and apparently the temperature in the indoor spaces is reduced. Thus, the results clearly indicate that the temperature in the indoor spaces of the hollow block building envelope was comparatively low when compared to the other two building materials.

Understanding the interaction between human activities and physical health under extreme heat environment in Phoenix, Arizona.

Long-term community resilience, which privileges a long view look at chronic issues influencing communities, has begun to draw more attention from city planners, researchers and policymakers. In Phoenix, resilience to heat is both a necessity and a way of life. In this paper, we attempt to understand how residents living in Phoenix experience and behave in an extreme heat environment. To achieve this goal, we introduced a smartphone application (ActivityLog) to study spatio-temporal dynamics of human interaction with urban environments. Compared with traditional paper activity log results we have in this study, the smartphone-based activity log has higher data quality in terms of total number of logs, response rates, accuracy, and connection with GPS and temperature sensors. The research results show that low-income residents in Phoenix mostly stay home during the summer but experience a relatively high indoor temperature due to the lack/low efficiency of air-conditioning (AC) equipment or lack of funds to run AC frequently. Middle-class residents have a better living experience in Phoenix with better mobility with automobiles and good quality of AC. The research results help us better understand user behaviors for daily log activities and how human activities interact with the urban thermal environment, informing further planning policy development. The ActivityLog smartphone application is also presented as an open-source prototype to design a similar urban climate citizen science program in the future.

중국 지린성 옌지시(吉林省延吉市) 조선족 고령자의 의생활 및 자각적 온열 감각

This study explores self-identified thermal perception and wearing habits of elderly Korean Chinese in Yanji city, Northeast China. Responses from a total of 193 participants were analyzed: 51 males and 142 females. Participants answered thirty-one questions concerning the following: wearing habits, thermoregulatory behavior, selfidentified cold tolerance, thermal perception, and heating conditions, etc. The results showed that the indoor temperature in Yanji was kept sufficiently warm during the heating period due to district heating, but a high percentage of respondents wore thermal underwear not only outdoors but also indoors. And only 14.7% of respondents said they were not vulnerable to cold (male 25.5%, female 10.8%, P = 0.022). Nevertheless, when asked what outdoor temperature they thought that it was cold in winter, they answered that the temperature was below -16.2 ± 8.2℃, which is very low. Interestingly, 76.6% answered that they preferred indoor temperature in winter above 24℃, which is relatively warm. 98.9% said they were supplied with district heating in the winter. Over many years, elderly Korean Chinese have adapted to both high indoor temperatures and harsh outdoor cold. Accordingly, it seems that their wintertime indoor and outdoor thermal perception have developed separately in winter.

Impacts of residential indoor air quality and environmental risk factors on adult asthma-related health outcomes in Chicago, IL.

Residential environments are known to contribute to asthma. To examine the joint impacts of exposures to residential indoor and outdoor air pollutants and housing risk factors on adult asthma-related health outcomes. We analyzed >1-year of data from 53 participants from 41 homes in the pre-intervention period of the Breathe Easy Project prior to ventilation and filtration retrofits. Health outcomes included surveys of asthma control, health-related quality of life, stress, and healthcare utilizations. Environmental assessments included quarterly measurements of indoor and outdoor pollutants (e.g., HCHO, CO, CO2, NO2, O3, and PM), home walk-throughs, and surveys of environmental risk factors. Indoor pollutant concentrations were also matched with surveys of time spent at home to estimate indoor pollutant exposures. Cross-sectional analyses using mixed-effects models indicated that lower annual average asthma control test (ACT) scores were associated (p < 0.05) with higher indoor NO2 (concentration/exposure: β = -2.42/-1.57), indoor temperature (β = -1.03 to -0.94), and mold/dampness (β = -3.09 to -2.41). In longitudinal analysis, lower ACT scores were also associated (p < 0.05) with higher indoor NO2 concentrations (β = -0.29), PM1 (concentration/exposure: β = -0.12/-0.24), PM2.5 (concentration/exposure: β = -0.12/-0.26), and PM10 (concentration/exposure: β = 10.14/-0.28). Emergency department visits were associated with poorer asthma control [incidence rate ratio (IRR) = 0.84; p < 0.001], physical health (IRR = 0.95; p < 0.05), mental health (IRR = 0.95; p < 0.05), higher I/O NO2 ratios (IRR = 1.30; p < 0.05), and higher indoor temperatures (IRR = 1.41; p < 0.05). Findings suggest that residential risk factors, including indoor air pollution (especially NO2 and particulate matter), higher indoor temperature, and mold/dampness, may contribute to poorer asthma control. This study highlights the importance of residential indoor air quality and environmental risk factors for asthma control, health-related quality of life, and emergency department visits for asthma. Two timescales of mixed models suggest that exposure to indoor NO2 and particulate matter, higher indoor temperature, and mold/dampness was associated with poorer asthma control. Additionally, emergency department visits were associated with poorer asthma control and health-related quality of life, as well as higher I/O NO2 ratios and indoor temperatures. These findings deepen our understanding of the interrelationships between housing, air quality, and health, and have important implications for programs and policy.

An analysis into the alternative strategies of substantial energy saving for the facilities of University of Jeddah, Khulais branch

The main objective of this study is to develop strategies which aim to improve the energy saving and the sustainability at the University of Jeddah (UJ) - Khulais branch. The energy saving can be improved by reducing -indirectly- the cooling load, while the sustainability can be improved by recycling the sewage water, generating energy from the solar irradiance and improving land-use efficiency. Initially, the main reasons for increasing energy consumption in the buildings were identified. The most important reasons were large heat gain through the flat rooftops and sidewalls, infiltration and exfiltration, partial damage to the insulation materials of walls and ceilings, and thermal mass. To reduce the heat gained through buildings' rooftops, it is proposed to shade the rooftops by tilted and ventilated airgap Building Integrated Photovoltaic (BIPV). BIPV also help to improve the shading efficiency, land use efficiency, natural cooling of the rooftops and PV modules, Energy Efficiency Rating (EER) of the air-cooled ac system, and efficiency of night ventilation system. To reduce heat gained through the sidewalls, it is proposed to shade the walls by planting long-stemmed trees (Eucalyptus) around the buildings. Irrigating the trees by gray water will improve the sustainability and improve Leed Credit Point. Previous studies and current measurements of solar radiation under shaded surfaces have shown that shading the building is an appropriate strategy to reduce solar heat gain. Startup load of air conditioning system is another source of increasing energy use and it forms around 10-20% of the total cooling load due to high indoor temperature at the morning. As the buildings are not occupied after 3:00 PM, and during weekends, it is proposed to use mechanical night ventilation to reduce the indoor temperature and to improve the air quality. Connecting the ventilation system with a separate control system and the BMS at the buildings help to reach to the possible minimum indoor temperature.