High Occupant Density Research Articles

Assessing evacuation risks in prominent historical mosques: An integrated quantitative and qualitative approach via the HM-ERI framework

Historical mosques, with their unique architectural features and high occupant densities, pose distinct challenges for safe and efficient evacuation. This study introduces the Historical Mosque Evacuation Risk Index (HM-ERI), a novel and comprehensive framework specifically designed to assess evacuation risks in these culturally significant structures. The HM-ERI model integrates three quantitative criteria derived from agent-based simulations and seventeen qualitative criteria assessed through on-site evaluations, generating two dimensionless risk scores: HM-ERIQN (quantitative risk) and HM-ERIQL (qualitative risk).Analysis of 12 prominent 15th and 16th century mosques in Turkey revealed a spectrum of evacuation risk levels. The mosques' HM-ERIQN values ranged from 0.27 (low risk) to 0.80 (high risk) in the range of 0–1, indicating variations in potential congestion and evacuation efficiency based on simulated total evacuation times ranging from 2 min 46.3 s to 8 min 18.5 s. HM-ERIQL values, reflecting the severity of qualitative factors on a 0–1 scale such as the lack of alternative exits, improper placement of shoe racks, complex building layouts, and limited emergency preparedness, fell between 0.46 and 0.73, indicating moderate to high risks.By integrating expert judgment and utilizing data from both simulations and on-site observations, the HM-ERI framework provides a practical tool for identifying high-risk historical mosques and informing targeted interventions to enhance evacuation safety. This research contributes to developing enhanced evacuation standards for these culturally significant structures, enabling improved safety evaluations and guiding effective preservation strategies that prioritize human life and cultural heritage.

Optimizing phased-evacuation strategy for high-rise buildings in fire

Evacuation in high-rise buildings is a critical safety issue due to multiple floors and high occupant density. Phased evacuation strategies can mitigate this challenge. This research focuses on developing optimal phased evacuation strategies to enhance occupant safety during high-rise building fires. The study demonstrates these strategies in a 25-story building, housing 2400 individuals, across various scenarios. To simulate fire and smoke development, a two-zone model is employed to analyze behavior within the building. Pedestrian evacuation scenarios are simulated using Pathfinder and a mathematical model, providing insights into individual movements and congestion during evacuation to analyze different phased evacuation strategies. Findings underscore the importance of smoke flow and pedestrian motion in optimizing phased evacuation strategies. The modeling results show that implementing the optimal strategy can lead to a 65 % reduction in staircase congestion time. This study provides a quantitative analysis of high-rise building fires, considering dynamic fire and evacuation evolution. It emphasizes the importance of phased evacuation strategies and advocates for their real-life application. This research enhances the understanding of high-rise building evacuations to improve safety measures and provides a robust framework for optimizing evacuation strategies by integrating fire modeling. This study demonstrates the effectiveness of phased evacuation and paves the way for future applications to ensure occupant safety in fire emergencies.

Energy-efficient operation of portable air cleaners based on real-time prediction of non-uniform concentrations of indoor air pollutants in open offices

In an open office environment with high occupant density and random occupancy patterns, excessive energy consumption is often observed because mechanical ventilation (MV) is usually designed and operated assuming a full-occupancy-based ventilation rate (VR). Considering the duo challenges of post-pandemic and climate change, this study proposes a real-time monitoring and optimization approach for operating portable air cleaners (PACs) to assist and reduce the energy consumption of the MV while maintaining the minimal VR and improving indoor air quality (IAQ). The approach was as follows. First, by assuming four VRs and 36 different emission sources, numerical simulations were conducted and validated based on an actual open office on non-uniform concentrations of a surrogate for indoor air pollutants (IAPs) throughout the breathing zone. Second, the pre- and post-purified IAP distributions were obtained using a limited number of sensors and trained by two artificial neural networks. Third, the real-time optimization of PACs’ on/off operation and placements was accomplished by the particle swarm optimization algorithm to balance energy output and improve IAQ simultaneously. Results showed that by deploying four sensors, the predictions of post-purifying concentrations were in acceptable accuracy (i.e., CV-RMSE <2.0%) within 30–40s. Using at most three PACs resulted in a significant decline in local IAP concentration levels. Meanwhile, an average reduction of total energy consumption of MV and PACs was 34.6% compared to using MV to reach the same levels. Overall, this study supports the use of PACs to assist MV in achieving energy efficiency and good IAQ.

Numerical evaluation of space form design for outpatient waiting space to reduce airborne infection risk in hospitals

The outpatient waiting space (OWS), with high density and frequent variations of occupants, represents a high-risk space for the spread of respiratory infectious diseases (RIDs) in hospitals. While previous studies have proposed strategies related to occupant behavior and environmental quality, there is a limited exploration of the impact of space form design on infection risk in OWSs. This study developed a numerical method for assessing the airborne infection risk, considering the non-uniform distribution of infectious particles and variations in occupant distributions. Validated computational fluid dynamics (CFD) simulations were employed to calculate the particle distributions. The intake fraction, accumulated throughout the waiting process, was then integrated into the Wells-Riley model for risk evaluation. Using the typical ventilation form of ceiling supply and ceiling return, with an air change per hour (ACH) set to 6 h−1 as the baseline, 12 typical space forms, including four space shapes (L shape, T shape, U shape, and O shape) and three entrance layouts (single-side entrance, middle entrance, and double-side entrances), were selected for comparisons. The results showed significant variations in infectious particle distributions across the 12 space forms, with average infection probabilities (IPs) ranging from 3.47 % to 19.75 %, suggesting that appropriate space form design has the potential to reduce IP by 16.28 %. These findings offer a novel perspective on mitigating airborne infection risk in hospitals by emphasizing the significance of architectural design. Moreover, precise space design guidance is proposed for OWS to safeguard human health against the spread of RIDs.

Regional High-Rise Building Fire Risk Assessment Based on the Spatial Markov Chain Model and an Indicator System

High-rise buildings (HRBs) are prone to high fire hazards due to their high occupant density, limited evacuation routes, and high fire load. The indicator system method, as a systematic evaluation method, is widely applied to assess HRB fire risk. However, the method is subjective because the determination of the indicator weights mainly relies on expert experience. In order to reduce the subjectivity of the indicator system method in assessing the fire risk of HRBs, this study proposes a new assessment method by combining the spatial Markov chain model and the indicator system method. In this new method, fire occurrence probability is calculated by the spatial Markov chain model using historical HRB fire accident data. An indicator system is built to characterize the fire consequence by the structure entropy weight method. Subsequently, HRBs in Beijing are used as a case to illustrate the practicality of this approach. Firstly, the spatial Markov chain model is trained and validated using the chi-square goodness-of-fit test based on fire accident data from 2018 to 2023 in Beijing. It was found that the best performance was achieved with the monthly period and the four-state. Then, the distribution of regional fire occurrence probability in April was predicted based on fire accident data in March 2023 in Beijing. It showed that areas with higher fire occurrence probability are mainly located in the central region, especially in the I District. Then, the indicator system was used to evaluate the HRB fire consequence in the I District. The assessment results showed that the areas with more severe fire consequences are mainly located in the II and IV Districts, due to the poor performance of the fire system or the absence of fire protection systems. Coupling the fire occurrence probability and its consequences shows that HRBs with higher fire risk are mainly located in area II and should be carefully supervised for fire management. This developed method can provide some insights into the fire safety management of HRBs and the layout of the fire stations.

Demand-Oriented Review of a Dynamic Energy-Loss Monitoring System for Primary School Buildings through Micro-Environmental Data Monitoring and Occupant Behavior Analysis

The utilization of primary school buildings is multifaceted, primarily due to the high occupancy density, varying thermal preferences among occupants, diverse indoor activities (such as walking, sports, and conversation), and a constant flow of individuals entering and exiting the building. This results in the frequent opening and closing of external windows and doors and fluctuations in internal heat gain. Consequently, frequent interactions between the indoor and outdoor microenvironments lead to energy losses. This study conducts a comprehensive literature review on building energy loss stemming from occupant behavior and the interactions between indoor and outdoor microenvironments. Furthermore, it proposes a dynamic real-time monitoring system based on a foundation of computer data capture and a visualization platform for building energy loss. The research methods include data crawling, data association rule mining, and data association analysis. The research findings yield a universally applicable and informative building energy-saving design system based on extensive data analysis. Additionally, the system presents information on occupants’ behavior and the microclimate data of indoor and outdoor environments on a computer screen, facilitating human–machine communication and enabling timely adjustments to be made, thus facilitating the construction of design strategies for new buildings and operation and maintenance strategies for existing buildings.

Air-type photovoltaic thermal (PVT) system connected to heat recovery ventilators installed in typical classroom

Air-type photovoltaic–thermal (PVT) systems do not experience leakage and are more practical than water-type systems. However, utilizing the collected heat is less straightforward owing to challenges in heat storage. This study proposes an air-type PVT system linked to a heat recovery ventilator targeted at school classrooms, where the required ventilation is high because of the high occupant density. Because buildings are mainly used during the daytime when solar radiation exists, it seems ideal as an application for air-type PVT systems without heat storage. The TRNSYS PVT model was calibrated using the performance test results of a PVT module developed for an actual school installation. Furthermore, a control plan for the air-conditioning and ventilation systems used in an actual school was proposed, and its effect was analyzed using simulations. The effect of increasing the temperature of the supply air was confirmed through an analysis using the proposed technology. A reduction in the ventilation load decreases the heating energy consumption of the electric heat pump by 15.43%. Furthermore, the PVT temperature reduction effect boosted the power production by 5.42% compared to the reference, and a total energy-saving effect of 18.72% was achieved.

Development of a process for flame retardant coating of textiles with bio-hybrid anchor peptides

The fire protection of materials has an important role in our everyday life and covers a highly diverse spectrum of substances, materials, and fields of application. Important fields of application for fire protection, especially in public areas, are construction and transport, electronic devices, furnishings, and textiles (e.g., applications for occupational safety, carpets, curtains, upholstery, insulation, and technical applications in outdoor areas). The efficient and durable finishing of materials with flame retardant additives is crucial to ensure effective fire protection. Many of the flame retardant additives currently used are based on bromides, chlorides, phosphates, or antimony. However, these flame retardants are harmful to the environment and/or health (not phosphates). Therefore, the use of these flame retardants is already being restricted by EU directives (e.g., REACH regulation), and it is foreseeable that they will be further restricted in the future. To keep up with this development, innovative and sustainable solutions must be developed in the short term. The amount of flame retardant additives that are harmful to the environment and health must be reduced. In the medium term, these harmful additives must be completely replaced by sustainable flame retardant additives that are not harmful to the environment and health. This paper describes research results to reduce the amount of additives in the short term. In order to reduce the amount of additives used, an innovative refinement process is being developed. In a first step, the flame retardant additives are combined with bio-based adhesion promoters (anchor peptides). Anchor peptides bind with high selectivity, binding strength, and occupancy density to a broad portfolio of materials (e.g., synthetic polymers, metals, ceramics, and natural materials) and enable the finishing of the materials with a broad spectrum of functional units (e.g., flame retardant additives). Material functionalization by anchor peptides is energy-efficient and resource-saving at room temperature in aqueous solution and is scalable in its production. Based on these developments, in this paper, a finishing process is presented with which flame retardant textiles can be equipped with bio-based anchor peptides. A requirements’ outline for the new finishing process is described. Established processes (e.g., foulard, coating machine, and roller application) are compared with each other and evaluated with regard to the requirements and their suitability. The most suitable process is then designed, and a laboratory scale as well as an industry scale concept are presented.

A Monte Carlo Assessment of the Effect of Different Ventilation Strategies to Mitigate the COVID-19 Contagion Risk in Educational Buildings

The COVID-19 pandemic outbreak has increased the general awareness of the importance of proper ventilation in the indoor environment to reduce the contagion risk. In particular, attention has been paid to specific categories of buildings, such as schools, due to two factors: (1) high occupancy density and (2) the presence of young and sometimes more susceptible people. Despite the high level of alertness towards the ventilation of classrooms, robust analyses of the effectiveness of the different strategies to mitigate the contagion risk have been difficult to perform. Indeed, the COVID-19 pandemic is still ongoing, and many factors, such as the presence of multiple viral strains, use of facial masks, progression in vaccination, and installation of air purifiers and other sanitization devices, make it difficult to fully quantify the impact of room ventilation by simply analysing available monitoring data. Moreover, mitigation strategies related to ventilation are often dynamic, increasing the complexity of the problem to assess. In this framework, this work proposes a new Monte Carlo method integrated with building performance simulation to evaluate the number of infected occupants under different scenarios, considering also the dynamic boundary conditions. The described approach has been applied to a case study classroom at the Free University of Bozen-Bolzano, Italy, analysing almost 100 different scenarios and discussing the effectiveness of different ventilation strategies traditionally adopted to ensure suitable IAQ according to CO2 concentration limits. Results highlight the importance of combining different solutions (e.g., mixed-mode ventilation and facial masks) to limit the risk for both students and lecturers.

Study on the optimization for emergency evacuation scheme under fire in university building complex

The evacuation in the university building complex involving a variety of campus buildings and a high density of occupants is barely simulated, especially by considering the safety awareness of evacuees and the impact of measured stair evacuation speed. This paper simulates and optimizes the fire emergency evacuation scheme of a university building complex in Northwest China by using BIM technology and Pathfinder simulation evacuation software. The proposed evacuation optimization scheme of university building complex reduces the evacuation time by 15–20% compared with the original evacuation scheme of the university. Through the simulation, it is found that the evacuation time required for sleeping at night is the shortest, while the longest evacuation time is required during lunch, due to the dispersion of students. Therefore, in addition to considering the safety awareness of the evacuees and the measured evacuation speed of stairs, the corresponding campus evacuation plan should be formulated according to the distribution of buildings in the campus complex and the actual utilization in different periods, so as to avoid the safety exit congestion and being far away from the refuge, due to the dense population in a specific period of time. This study also provides a method for solving the problem of regional evacuation path planning.

Evaluation of hygrothermal comfort in educational centres by monitoring three case studies with different ventilation systems in Vitoria, Spain

Indoor Environmental Quality has an impact on the health of its users, especially in educational centres due to the vulnerability of its occupants and high occupancy density. This study aims to analyse the hygrothermal comfort of three case studies with different ventilation systems located in the same city by monitoring. For this purpose, a three-phase methodology was proposed. First, a characterization of the case studies has been made. Second, the results obtained in the monitoring of temperature, relative humidity and CO2 concentration during the occupied period have been analysed. Third, the hygrothermal comfort according to UNE-EN 16798 for each classroom has been compared. As a result, overall better comfort is achieved during summer than in winter. The ventilation system used in each centre has not had a great impact comparing the classrooms, being all of them in comfort for more than 80% of the occupied period. All classrooms had comfortable temperatures more than 80% of the time in summer and 70% in winter but the gymnasiums presented very low temperatures, especially during winter. In conclusion, comfort has been achieved as well in naturally as in mechanically ventilated classrooms.

Identifying occupancy patterns and profiles in higher education institution buildings with high occupancy density – A case study

ABSTRACT Building occupancy patterns are an important factor in considering the energy efficiency of buildings and a key input for building performance modelling. More specifically, the energy consumption associated with heating, cooling, lighting, and plug load usage depends on the number of occupants in a building. Identifying occupancy patterns and profiles in buildings is a key factor for the optimisation of building operating systems and can potentially reduce the performance gap between the planning stage and the actual energy usage. This study aims to identify the patterns and profiles of the occupants in a selected case study building in England. In this study, occupancy data were collected over 12 months at five minutes intervals. A sensor was used to obtain high accuracy occupancy data compared to previous studies that encountered uncertainties in data collection. A set of clustering analyses was carried out to identify occupancy patterns and profiles in the building. The results of this study identified three different occupancy patterns and profiles as well as four drivers that influenced the occupants in the case study building: the beginning of the academic term, the examination period, the weekday/weekends, and the vacation driver.

Development of a Bayesian inference model for assessing ventilation condition based on CO2 meters in primary schools.

Outdoor fresh air ventilation plays a significant role in reducing airborne transmission of diseases in indoor spaces. School classrooms are considerably challenged during the COVID-19 pandemic because of the increasing need for in-person education, untimely and incompleted vaccinations, high occupancy density, and uncertain ventilation conditions. Many schools started to use CO2 meters to indicate air quality, but how to interpret the data remains unclear. Many uncertainties are also involved, including manual readings, student numbers and schedules, uncertain CO2 generation rates, and variable indoor and ambient conditions. This study proposed a Bayesian inference approach with sensitivity analysis to understand CO2 readings in four primary schools by identifying uncertainties and calibrating key parameters. The outdoor ventilation rate, CO2 generation rate, and occupancy level were identified as the top sensitive parameters for indoor CO2 levels. The occupancy schedule becomes critical when the CO2 data are limited, whereas a 15-min measurement interval could capture dynamic CO2 profiles well even without the occupancy information. Hourly CO2 recording should be avoided because it failed to capture peak values and overestimated the ventilation rates. For the four primary school rooms, the calibrated ventilation rate with a 95% confidence level for fall condition is 1.96±0.31 ACH for Room #1 (165 m3 and 20 occupancies) with mechanical ventilation, and for the rest of the naturally ventilated rooms, it is 0.40±0.08 ACH for Room #2 (236 m3 and 21 occupancies), 0.30±0.04 or 0.79±0.06 ACH depending on occupancy schedules for Room #3 (236 m3 and 19 occupancies), 0.40±0.32,0.48±0.37,0.72±0.39 ACH for Room #4 (231 m3 and 8–9 occupancies) for three consecutive days.

Examination and optimization of classroom indoor environments in China’s hot summer and cold winter regions

The school’s indoor environment significantly affects students’ health and learning performance. Although related studies have been carried out in many regions, only a few have examined indoor classroom environments and proposed the energy-saving optimization of heating and ventilation in winter in China’s hot summer and cold winter areas. This study aims to comprehensively investigate classroom indoor environmental quality in China’s hot summer and cold winter areas, and propose targeted optimization strategies. It first examined the indoor environment, including indoor air, acoustic, visual, and thermal quality, of two typical middle schools. The indoor CO2 concentration in winter was found to be unsatisfactory. Subsequently, how the indoor layout, outdoor wind and occupancy density influence indoor CO2 concentration was examined through simulation, which indicated that high occupancy density is the main cause. Finally, this study proposed several ventilation optimization strategies and performed an energy analysis to maintain sufficient air quality and a comfortable thermal environment in high-density classrooms. The results show that compared with the intermittent mode, the fixed ventilation and heating mode could maintain a more comfortable indoor environment and achieve a 30% energy saving. A reference for the improvement of classroom indoor environment in hot summer and cold winter areas was provided.

Very high-resolution remote sensing-based mapping of urban residential districts to help combat COVID-19

Urban residential districts (URDs) are a major element in the formation of cities that are essential for urban planning. Regarding the COVID-19 virus, which remains variable in aerosols for several hours, airborne transmission tends to occur in areas of poor ventilation and high occupant density. Thus, ventilation capacity is an important factor influencing airborne transmission in URDs, which should be evaluated as part of efforts to fight COVID-19 and guide healthy city planning and implementation. Here, we develop and test systematic methods to map URDs in a typical city in northern China and quantify their ventilation capacity using very high-resolution remote sensing images. Four fundamental spatial forms of URD are identified in the research area: the point-group form, parallel form, enclosed form, and hybrid form. Our analyses indicate that the integrated ventilation capacities for well-designed URDs are nearly twice those of poorly designed URDs. Large variations in ventilation capacity are also observed within URDs, with up to 13.42 times difference between the buildings. Therefore, very high-resolution remote sensing data are fundamental for extracting building height and generating precise spatial forms, which can improve the micro-scale URD ventilation planning for the prevention of COVID-19.

Optimization of environment control system for narrow sleeping space in underground shelters

As one of the main functions of urban underground spaces, underground shelter can be utilized for prevention/mitigation of disasters. In underground shelter, narrow sleeping spaces are recommended due to cost-effective and space-saving charcteristics. However, it is challenging to create a satisfied indoor environment with narrow sleeping spaces because of the limited space, high density of occupants and complex physical fields. In this study, an environmental control system was proposed for narrow sleeping spaces with multiple occupants, and numerical simulations were adopted in design and optimization process. Firstly, a numerical strategy (including turbulence modeling, meshing method and experimental validation) was proposed for the environment control system. Secondly, the validated numerical model was adopted to investigate the influences of key design parameters (such as inlet air velocity, temperature, air supply angle and airflow pattern) on indoor environment and energy consumption of narrow sleeping spaces with airflow pattern of “Up-supply and Down-return”. Thirdly, the CFD-GA (Genetic Algorithm) method was utilized to optimize multiple design parameters of the environment control system. The optimal results indicated that all of the indexes (predicted percentage dissatisfied [PPD], percentage dissatisfied of draft sensation [PD] and carbon dioxide [CO2] concentration) satisfied the requirement of standards, and its energy consumption was much lower than other design conditions. Compared to the “Up-supply and Down-return” airflow pattern, the “Down-supply and Up-return” airflow pattern produced higher PD values and caused stronger draft sensation. Overall, the numerical strategy and CFD-GA optimization method is able to provide proper design of indoor environment control for the underground narrow sleeping space, from the perspectives of thermal comfort, air quality and energy saving.

Inactivation of MS2 bacteriophage on copper film deployed in high touch areas of a public transport system.

Although SARS-CoV-2 is primarily an airborne risk, the COVID-19 pandemic also highlighted the need for self-disinfection surfaces that could withstand the demand of high occupant densities characteristic of public transportation systems. The aim of this study was to evaluate the durability and antiviral activity of a copper film deployed for 90 days in two high touch locations within an active metropolitan bus and railcar. The antiviral efficacy of this copper film after being deployed in transit vehicles for 90 days (deployed copper film) was then compared to new (unused) copper film to determine if frequent touches and cleaning protocols could decrease the efficacy of the copper films. Deployed copper film, new copper film, and aluminium foil (positive control) coupons were inoculated with ~1 × 106 MS2 virus particles, allowed a contact time of either 5- or 10-min, and analysed for residual viral infectiousness. On both new and deployed copper films, MS2 was completely inactivated (≥5 log reduction) at both time points. These results suggest that the copper film may provide the durability demanded by high touch public spaces while maintaining the antiviral activity necessary to reduce exposure risk and viral transmission via surfaces in public transportation settings.

Performance evaluation of intermittent air supply system: a case study in Xi’an

Intermittent air jet strategy (IAJS) has been proven to provide a satisfactory indoor thermal climate with high energy efficiency in spaces with high occupancy density. Compared with traditional ventilation strategy, IAJS system creates heterogeneous conditions around the occupants, which complicates the relationship between thermal sensation and thermal comfort. The effect of different intermittent cycles on the thermal comfort of occupants needs to be further discussed. In addition, it is necessary to investigate whether IAJS system can play a better role in hot and humid summer conditions in China. Experiments were conducted in a chamber with two rows of seated occupants. Twelve cases were designed, including different combinations of room air temperatures (24°C, 26°C and 28°C) and intermittent period (start 90 s stop 90 s, start 3 min stop 1.5 min, start 1.5 min stop 3 min and start 3 min stop 3 min). Twelve subjects were recruited for subjective investigations. The subjects performed sedentary work and wore summer clothing. Subjective responses to the thermal environments were collected. Wind speed, temperature and CO2 concentration in the occupied area were measured. The results show that IAJS has a potential to be used as a primary ventilation system primary ventilation system such as classrooms in China. When the indoor air was set between 24°C and 26°C, IAJS could create a thermal climate that made the occupants thermally neutral. Additionally, IAJS created an indoor thermal environment acceptable to most occupants, even at a setting temperature of 28 °C.

Diurnal variation and potential sources of indoor formaldehyde at elementary school, high school and university in the Centre Val de Loire region of France

Formaldehyde (HCHO) is one of the abundant indoor pollutants and has been classified as a human carcinogen by the International Agency for Research on Cancer (IARC). Indoor HCHO at schools is particularly important due to the high occupancy density and the health effects on children. In this study, high time resolved measurement of formaldehyde concentration was conducted in the classrooms at elementary school, high school and university under normal students' activities in three different locations in the Region Centre Val de Loire-France. Indoor average formaldehyde concentrations at those three educational institutions were observed to be in the range 10.96–17.95 μg/m3, not exceeding the World Health Organization (WHO) guideline value of 100 μg/m3. As expected, ventilation was found playing an important role in the control of indoor formaldehyde concentration. After opening windows for 30 min, formaldehyde level decreased by ~25% and 38% in the classroom at the elementary school and the high school, respectively. In addition to the primary sources, the objective of this study was also to determine potential secondary sources of indoor formaldehyde in these schools by measuring the other volatile organic compounds (VOCs) present in the classrooms by a Proton Transfer Reaction Time-of-Flight Mass Spectrometry (PTR-ToF-MS). The measurements suggest that the release of residue from tobacco smokers is one of the major sources of indoor HCHO at the high school, which increases HCHO by ~55% averagely within 1 h. Moreover, the control experiments conducted in the university suggests that VOCs such as that released from cleaning products like terpenes, can contribute to the increase of indoor formaldehyde levels through chemical reactions with ozone. This study confirms simple recommendations to reduce the indoors HCHO concentration in schools: use ventilation systems, limit the emissions like cigarette smoke or cleaning products. It also points out that the secondary sources of formaldehyde must be also considered in the classroom.

Design of Flat With Neighborhood Space With Urban Farming Function In Medan

In Medan, flats do not utilize neighborhood space as an urban farming area. In general, flats have a high density of occupants, inflexible designs, and the relationship between one door to another door is relatively close so that communal space is needed. Communal space is a space that functions as a place for social interaction activities for its residents. This flat design has green open spaces such as neighborhood space that can be used as communal spaces both socially and economically productively (urban farming) because flats require both functions. The design approach process used in this design is primary data collection through a field study process and physical data collection that supports scientific and factual data processing. The design analysis was carried out based on the results of literature review and data collection to identify the character of the design area, problems that arise, limitations and potentials, functional requirements, then conduct a review of the regional development plan. This flat is designed using an Ecological Architecture approach to reduce environmental problems in urban areas. The design creates a flat that considers the needs of communal space, green open space, and recreation areas to meet the needs of users. This design can create facilities for the community and become a tourist attraction.