Pub Date : 2024-08-22DOI: 10.1177/1420326x241270825
Xiaoyi Chen, Ziqiao Li, Longkang Dai, Meng Liu
Clean heating, represented by the ‘coal-to-electricity’ program, is considered a key strategic approach to addressing severe air pollution in northern China. However, the transition to air-to-air heat pump (AAHP) electrical heating in rural households can significantly impact the electricity load. Therefore, it is crucial to quantify and analyze baseline load characteristics of transitioning to electric heating in rural areas. This study evaluated variations in rural baseline load characteristics under four typical heating patterns and four scenarios with different electric heating transformation rates and heating demands. The results indicate no significant difference in the original baseline load between weekdays and weekends in rural areas. Under the four typical heating patterns, the peak-valley ratio increases while the load rate decreases. In particular, the intermittent heating patterns exhibit peak-valley ratios ranging from 0.89 to 0.95 and load rates ranging from 0.21 to 0.39. When the AAHP heating transformation rates exceed 50%, an increase in substation power supply capacity is needed. Furthermore, under different heating scenarios, the average peak-valley ratios of rural power substations range from 0.41 to 0.60, suggesting significant potential for demand response. These findings have significant implications for energy security and energy planning in rural areas.
{"title":"Baseline load characteristics of transitioning to air-to-air heat pump electric heating in rural areas of northern China","authors":"Xiaoyi Chen, Ziqiao Li, Longkang Dai, Meng Liu","doi":"10.1177/1420326x241270825","DOIUrl":"https://doi.org/10.1177/1420326x241270825","url":null,"abstract":"Clean heating, represented by the ‘coal-to-electricity’ program, is considered a key strategic approach to addressing severe air pollution in northern China. However, the transition to air-to-air heat pump (AAHP) electrical heating in rural households can significantly impact the electricity load. Therefore, it is crucial to quantify and analyze baseline load characteristics of transitioning to electric heating in rural areas. This study evaluated variations in rural baseline load characteristics under four typical heating patterns and four scenarios with different electric heating transformation rates and heating demands. The results indicate no significant difference in the original baseline load between weekdays and weekends in rural areas. Under the four typical heating patterns, the peak-valley ratio increases while the load rate decreases. In particular, the intermittent heating patterns exhibit peak-valley ratios ranging from 0.89 to 0.95 and load rates ranging from 0.21 to 0.39. When the AAHP heating transformation rates exceed 50%, an increase in substation power supply capacity is needed. Furthermore, under different heating scenarios, the average peak-valley ratios of rural power substations range from 0.41 to 0.60, suggesting significant potential for demand response. These findings have significant implications for energy security and energy planning in rural areas.","PeriodicalId":13578,"journal":{"name":"Indoor and Built Environment","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142216278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-16DOI: 10.1177/1420326x241270775
Vahid Zamani, Shaghayegh Abtahi, Yuxiang Chen, Yong Li
Effective building energy management (e.g. temperature control strategies) necessitates reliable and computationally efficient building thermal models. One type of them is the resistor–capacitor (RC) model. However, estimating model parameters and inputs (e.g. solar heat gain) simultaneously is challenging, especially when some of the temperature states are missing due to instrumentation limitations and/or sensor malfunctions. The present study utilizes unscented Kalman filter (UKF) and nonlinear least squares (NLSs) methods for parameters and input estimation of RC models with possible unavailable temperature states. The estimation procedure, mathematical operations and result analysis are presented in detail. To evaluate the capability of the method, two case studies were conducted. The first case study involved a simple, made-up RC model with known parameters, inputs and states, while the second case study used monitored data from a single detached house. The capability of the method was evaluated by comparing the estimated parameters, inputs and states to the corresponding true values in both study cases. The performance evaluation shows that the proposed method can effectively estimate RC model parameters and inputs, even with certain missing states. The proposed method can be employed for timely online updating of RC model parameters to improve response prediction.
{"title":"Parameter-input estimation of RC thermal models of buildings using unscented Kalman filter and nonlinear least square method","authors":"Vahid Zamani, Shaghayegh Abtahi, Yuxiang Chen, Yong Li","doi":"10.1177/1420326x241270775","DOIUrl":"https://doi.org/10.1177/1420326x241270775","url":null,"abstract":"Effective building energy management (e.g. temperature control strategies) necessitates reliable and computationally efficient building thermal models. One type of them is the resistor–capacitor (RC) model. However, estimating model parameters and inputs (e.g. solar heat gain) simultaneously is challenging, especially when some of the temperature states are missing due to instrumentation limitations and/or sensor malfunctions. The present study utilizes unscented Kalman filter (UKF) and nonlinear least squares (NLSs) methods for parameters and input estimation of RC models with possible unavailable temperature states. The estimation procedure, mathematical operations and result analysis are presented in detail. To evaluate the capability of the method, two case studies were conducted. The first case study involved a simple, made-up RC model with known parameters, inputs and states, while the second case study used monitored data from a single detached house. The capability of the method was evaluated by comparing the estimated parameters, inputs and states to the corresponding true values in both study cases. The performance evaluation shows that the proposed method can effectively estimate RC model parameters and inputs, even with certain missing states. The proposed method can be employed for timely online updating of RC model parameters to improve response prediction.","PeriodicalId":13578,"journal":{"name":"Indoor and Built Environment","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142216281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-16DOI: 10.1177/1420326x241261854
Kai Lu, Zhen Ding, Hua Qian, Xiaohong Zheng
The outbreak of coronavirus disease 2019 (COVID-19) has had a significant impact on human life. Hybrid ventilated hospitals have emerged as multi-zone sites, necessitating ventilation strategies to mitigate viral concentration. This paper integrates multi-zone infiltration and exfiltration (MIX) model of natural ventilation, spatial flow impact factor (SFIF) model and pollutant concentration model to analyze the inter-zonal impact. Results indicate that elevated outdoor temperature corresponds to an increased influence of rooms on corridors. Adopting mechanical ventilation in rooms diminishes the influence of room pollutants on corridors but exerts minimal impact on other rooms. Mechanical air supply reduces the interaction between corridors, and the reduction is most significant when wind direction is the same as stairwell orientation. The corridors do not affect the upstream rooms when the source is in the corridor. When wind speed is below a threshold, mechanical air supply is recommended; for wind speed reaching this threshold, mechanical air exhaust volumes should be adjusted regarding the wind speed. The study reveals that corridor and room window openings exert disparate effects on corridor concentration under mechanical air supply conditions. All the findings offer valuable insights for selecting ventilation strategies in hybrid ventilated hospitals, with the aim of mitigating COVID-19 transmission.
{"title":"Positive or negative? The pressure control impact in hybrid ventilated hospitals","authors":"Kai Lu, Zhen Ding, Hua Qian, Xiaohong Zheng","doi":"10.1177/1420326x241261854","DOIUrl":"https://doi.org/10.1177/1420326x241261854","url":null,"abstract":"The outbreak of coronavirus disease 2019 (COVID-19) has had a significant impact on human life. Hybrid ventilated hospitals have emerged as multi-zone sites, necessitating ventilation strategies to mitigate viral concentration. This paper integrates multi-zone infiltration and exfiltration (MIX) model of natural ventilation, spatial flow impact factor (SFIF) model and pollutant concentration model to analyze the inter-zonal impact. Results indicate that elevated outdoor temperature corresponds to an increased influence of rooms on corridors. Adopting mechanical ventilation in rooms diminishes the influence of room pollutants on corridors but exerts minimal impact on other rooms. Mechanical air supply reduces the interaction between corridors, and the reduction is most significant when wind direction is the same as stairwell orientation. The corridors do not affect the upstream rooms when the source is in the corridor. When wind speed is below a threshold, mechanical air supply is recommended; for wind speed reaching this threshold, mechanical air exhaust volumes should be adjusted regarding the wind speed. The study reveals that corridor and room window openings exert disparate effects on corridor concentration under mechanical air supply conditions. All the findings offer valuable insights for selecting ventilation strategies in hybrid ventilated hospitals, with the aim of mitigating COVID-19 transmission.","PeriodicalId":13578,"journal":{"name":"Indoor and Built Environment","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142216280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-13DOI: 10.1177/1420326x241268257
Doudou Miao, Min Zhu, Zhikang Xu, Marco-Felipe King, Nan Zhang
During the COVID-19 pandemic, Chinese universities implemented many interventions against SAR-CoV-2 transmission. Close contact is thought to be a major transmission route. However, the effect of university closure-related interventions on infection risk amongst students is still poorly understood. In July 2022, we conducted an online survey of 2,400 university students in Beijing and Shanghai. Combined with real human behaviours, we evaluated the infection risk via close contact during both periods of university closures and non-closures. During the non-closure period, undergraduate and postgraduate students spent the longest close contact time in classrooms and graduate student offices, averaging 1.9 h and 2.2 h, respectively. During university closures, students spent the longest close contact time in residences (dormitories and homes), reaching up to 2.8 h. Catering places and residences were the two main indoor environments for viral exposure via close contact. Viral exposure did not differ significantly by education background or gender ( p > 0.05) but did by intervention levels in university or community ( p < 0.05). The infection risk decreased by 30.0% for resident students and 63.6% for non-resident students during university closures. The findings could provide scientific support for intervention policy-making during public health emergencies such as COVID-19 pandemic.
{"title":"University closures can reduce the risk of severe acute respiratory syndrome coronaviruses-2 transmission via close contact amongst Chinese students by over 60%","authors":"Doudou Miao, Min Zhu, Zhikang Xu, Marco-Felipe King, Nan Zhang","doi":"10.1177/1420326x241268257","DOIUrl":"https://doi.org/10.1177/1420326x241268257","url":null,"abstract":"During the COVID-19 pandemic, Chinese universities implemented many interventions against SAR-CoV-2 transmission. Close contact is thought to be a major transmission route. However, the effect of university closure-related interventions on infection risk amongst students is still poorly understood. In July 2022, we conducted an online survey of 2,400 university students in Beijing and Shanghai. Combined with real human behaviours, we evaluated the infection risk via close contact during both periods of university closures and non-closures. During the non-closure period, undergraduate and postgraduate students spent the longest close contact time in classrooms and graduate student offices, averaging 1.9 h and 2.2 h, respectively. During university closures, students spent the longest close contact time in residences (dormitories and homes), reaching up to 2.8 h. Catering places and residences were the two main indoor environments for viral exposure via close contact. Viral exposure did not differ significantly by education background or gender ( p > 0.05) but did by intervention levels in university or community ( p < 0.05). The infection risk decreased by 30.0% for resident students and 63.6% for non-resident students during university closures. The findings could provide scientific support for intervention policy-making during public health emergencies such as COVID-19 pandemic.","PeriodicalId":13578,"journal":{"name":"Indoor and Built Environment","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142216433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-04DOI: 10.1177/1420326x241268037
Jongwoo Cho, Kwonsik Song, Moonseo Park, Changbum R Ahn, Tae Wan Kim
This study investigated impact source ambiguity in box-frame multifamily buildings, prevalent in densely populated areas, by examining the transmission of heavy-impact noise and its relationship with junction attenuations across five floors. Contrary to the decline in noise levels with increased distance from the impact source, our findings uncover an intriguing deviation in the behaviour of vibration response levels. Surprisingly, vibrations are often intensified, rather than diminished, with distance. Notably, upon examining each room, instances where non-structural or thin concrete walls exhibited the highest vibration responses were frequently observed. Such instances were particularly prevalent in rooms not directly adjacent to the impact source. This trend markedly impedes residents’ ability to pinpoint the origin location of impact noises. This study reveals an unexpected weakening and reversal of distance attenuation in vibration, linked to the increasing number of valid flanking paths as the junction distance grows. The findings suggest that increasing slab thickness for noise insulation may unintentionally complicate source identification due to diminished junction attenuation in thicker horizontal components compared to vertical ones. To enhance acoustic comfort in such housing, this study recommends minimizing valid flanking paths through improved junction design, addressing an often-overlooked issue of source ambiguity of floor noises.
{"title":"Investigation of source ambiguity of floor noises in a box-frame concrete building from the perspective of junction attenuations: A real case field experiment","authors":"Jongwoo Cho, Kwonsik Song, Moonseo Park, Changbum R Ahn, Tae Wan Kim","doi":"10.1177/1420326x241268037","DOIUrl":"https://doi.org/10.1177/1420326x241268037","url":null,"abstract":"This study investigated impact source ambiguity in box-frame multifamily buildings, prevalent in densely populated areas, by examining the transmission of heavy-impact noise and its relationship with junction attenuations across five floors. Contrary to the decline in noise levels with increased distance from the impact source, our findings uncover an intriguing deviation in the behaviour of vibration response levels. Surprisingly, vibrations are often intensified, rather than diminished, with distance. Notably, upon examining each room, instances where non-structural or thin concrete walls exhibited the highest vibration responses were frequently observed. Such instances were particularly prevalent in rooms not directly adjacent to the impact source. This trend markedly impedes residents’ ability to pinpoint the origin location of impact noises. This study reveals an unexpected weakening and reversal of distance attenuation in vibration, linked to the increasing number of valid flanking paths as the junction distance grows. The findings suggest that increasing slab thickness for noise insulation may unintentionally complicate source identification due to diminished junction attenuation in thicker horizontal components compared to vertical ones. To enhance acoustic comfort in such housing, this study recommends minimizing valid flanking paths through improved junction design, addressing an often-overlooked issue of source ambiguity of floor noises.","PeriodicalId":13578,"journal":{"name":"Indoor and Built Environment","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141969308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-02DOI: 10.1177/1420326x241271507
Hui Zhu, Masanari Ukai, Fan Zhang, Chuck Wah Yu
{"title":"Mental fatigue evaluations in indoor environment","authors":"Hui Zhu, Masanari Ukai, Fan Zhang, Chuck Wah Yu","doi":"10.1177/1420326x241271507","DOIUrl":"https://doi.org/10.1177/1420326x241271507","url":null,"abstract":"","PeriodicalId":13578,"journal":{"name":"Indoor and Built Environment","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141884767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study investigated the effect of exhaust air volumes on the performance of range hoods at different angles in residential kitchens in removing grease pollutants, during the pollutant emission stage (whilst cooking) and the pollutant attenuation stage (after cooking). Experiments were conducted, and introduced indexes such as capture efficiency, exposure rate, attenuation rate, power and multi-indicator analysis were used to analyze the performance of the range hood with different exhaust air volumes and angles. The experimental results showed the capture efficiency was increased with an increase in exhaust air volume whilst cooking. Considering the energy consumption of the range hood and noise, the exhaust air volume of the range hood should be set at 600 m3/h to 800 m3/h. In the pollutant attenuation stage, the attenuation rate K of PM2.5 mass concentration was increased with the incremental increase in the exhaust air volume. When cooking was finished, grease pollutants remained in the kitchen. If the range hood continued to be turned on and a large exhaust air volume was set, the concentration of indoor grease pollutants could be quickly reduced to below the standard value. Our findings can provide a reference for the airflow regulation of residential kitchen range hoods.
本研究调查了在污染物排放阶段（烹饪时）和污染物衰减阶段（烹饪后），排风量对住宅厨房不同角度抽油烟机去除油烟污染物性能的影响。实验引入了捕获效率、暴露率、衰减率、功率和多指标分析等指标，分析了不同排风量和角度的抽油烟机的性能。实验结果表明，随着烹饪时排风量的增加，捕获效率也随之提高。考虑到抽油烟机的能耗和噪音，抽油烟机的排风量应设定为 600 m3/h 至 800 m3/h。在污染物衰减阶段，PM2.5 质量浓度的衰减率 K 随排风量的增加而增加。烹饪结束后，油烟污染物仍留在厨房中。如果继续开启抽油烟机并设置较大的排风量，室内油烟污染物的浓度可迅速降至标准值以下。我们的研究结果可为住宅厨房抽油烟机的风量调节提供参考。
{"title":"Performance analysis of range hoods with different exhaust air volumes","authors":"Huizhe Cao, Zhengkun Huang, Hao Wang, Jiankai Dong","doi":"10.1177/1420326x241269706","DOIUrl":"https://doi.org/10.1177/1420326x241269706","url":null,"abstract":"This study investigated the effect of exhaust air volumes on the performance of range hoods at different angles in residential kitchens in removing grease pollutants, during the pollutant emission stage (whilst cooking) and the pollutant attenuation stage (after cooking). Experiments were conducted, and introduced indexes such as capture efficiency, exposure rate, attenuation rate, power and multi-indicator analysis were used to analyze the performance of the range hood with different exhaust air volumes and angles. The experimental results showed the capture efficiency was increased with an increase in exhaust air volume whilst cooking. Considering the energy consumption of the range hood and noise, the exhaust air volume of the range hood should be set at 600 m<jats:sup>3</jats:sup>/h to 800 m<jats:sup>3</jats:sup>/h. In the pollutant attenuation stage, the attenuation rate K of PM<jats:sub>2.5</jats:sub> mass concentration was increased with the incremental increase in the exhaust air volume. When cooking was finished, grease pollutants remained in the kitchen. If the range hood continued to be turned on and a large exhaust air volume was set, the concentration of indoor grease pollutants could be quickly reduced to below the standard value. Our findings can provide a reference for the airflow regulation of residential kitchen range hoods.","PeriodicalId":13578,"journal":{"name":"Indoor and Built Environment","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141884760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-01DOI: 10.1177/1420326x241268085
Chengcheng Xu, Suola Shao, Wenjian Wei, Shuhong Li, Nan Li
Due to the popularization of high-speed rail (HSR), there have been increasing concerns of passengers about the thermal comfort of HSR air conditioning. The corrected predicted mean vote (CPMV) model considering the impact of solar radiation on indoor thermal comfort has been previously proposed and validated for accuracy in office buildings. To verify the accuracy of the CPMV model in evaluating the thermal comfort of passengers inside HSR carriages, the field study on HSR in the Yangtze River Delta region of China was conducted in winter and summer. The results indicate thermal sensation vote values obtained from passengers fit well with CPMV values. When the temperature is high in summer and low in winter, the CPMV model ignores people’s ability to adapt and tolerate harsh environments. In addition, the thermal preference temperature of passengers in summer is 0.57°C higher than the neutral temperature, indicating that there is an overcooling situation in summer. The study recommends to lower the set temperature of summer air conditioning in HSR. This study contributes to the promotion of the CPMV model on HSR and provides technical support for the design of air-conditioning systems for HSR carriages from the perspective of thermal comfort of passengers.
{"title":"Analysis of the application of CPMV model to the thermal comfort of passengers in high-speed rail carriages","authors":"Chengcheng Xu, Suola Shao, Wenjian Wei, Shuhong Li, Nan Li","doi":"10.1177/1420326x241268085","DOIUrl":"https://doi.org/10.1177/1420326x241268085","url":null,"abstract":"Due to the popularization of high-speed rail (HSR), there have been increasing concerns of passengers about the thermal comfort of HSR air conditioning. The corrected predicted mean vote (CPMV) model considering the impact of solar radiation on indoor thermal comfort has been previously proposed and validated for accuracy in office buildings. To verify the accuracy of the CPMV model in evaluating the thermal comfort of passengers inside HSR carriages, the field study on HSR in the Yangtze River Delta region of China was conducted in winter and summer. The results indicate thermal sensation vote values obtained from passengers fit well with CPMV values. When the temperature is high in summer and low in winter, the CPMV model ignores people’s ability to adapt and tolerate harsh environments. In addition, the thermal preference temperature of passengers in summer is 0.57°C higher than the neutral temperature, indicating that there is an overcooling situation in summer. The study recommends to lower the set temperature of summer air conditioning in HSR. This study contributes to the promotion of the CPMV model on HSR and provides technical support for the design of air-conditioning systems for HSR carriages from the perspective of thermal comfort of passengers.","PeriodicalId":13578,"journal":{"name":"Indoor and Built Environment","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141884769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Conventional air purifiers are low effective in inactivating airborne bacteria and may cause secondary contamination by releasing endotoxins. In this study, a novel air purifier was developed and used in a static chamber, which used slightly acidic electrolysed water (SAEW) solutions as the circulating disinfectant spray medium that automatically renewed every 30 min. During the 30-minute operation, the air and solution samples were collected to measure the bacteria and endotoxin concentration by using a culturable-based method and a limulus amoebocyte lysate assay kit, respectively. The pH and endotoxin of the circulating solution were gradually increased, and the available chlorine concentration (ACC, from 87 to 50 mg/L) was decreased. Although airborne bacteria were reduced significantly, the levels of airborne endotoxins at the inlet and outlet of the purifier remained constant. Moreover, a validation experiment revealed that SAEW, with ACC of 20, 60 and 100 mg/L, cannot inactivate standard endotoxin solutions. In the experimental chamber, the airborne bacteria level (1142 CFU/m3) was significantly lower compared to the control chamber (3325 CFU/m3), with no significant difference in airborne endotoxin levels between the chambers. Our results showed that the SAEW spray air purifier could effectively remove airborne bacteria without increasing airborne endotoxin levels within a 30-minute operational period.
{"title":"Design and performance evaluation of a novel slightly acidic electrolysed water spraying air purifier for airborne bacteria and endotoxin in indoor air","authors":"Chang Liu, Zonggang Li, Senzhong Deng, Weichao Zheng","doi":"10.1177/1420326x241268320","DOIUrl":"https://doi.org/10.1177/1420326x241268320","url":null,"abstract":"Conventional air purifiers are low effective in inactivating airborne bacteria and may cause secondary contamination by releasing endotoxins. In this study, a novel air purifier was developed and used in a static chamber, which used slightly acidic electrolysed water (SAEW) solutions as the circulating disinfectant spray medium that automatically renewed every 30 min. During the 30-minute operation, the air and solution samples were collected to measure the bacteria and endotoxin concentration by using a culturable-based method and a limulus amoebocyte lysate assay kit, respectively. The pH and endotoxin of the circulating solution were gradually increased, and the available chlorine concentration (ACC, from 87 to 50 mg/L) was decreased. Although airborne bacteria were reduced significantly, the levels of airborne endotoxins at the inlet and outlet of the purifier remained constant. Moreover, a validation experiment revealed that SAEW, with ACC of 20, 60 and 100 mg/L, cannot inactivate standard endotoxin solutions. In the experimental chamber, the airborne bacteria level (1142 CFU/m<jats:sup>3</jats:sup>) was significantly lower compared to the control chamber (3325 CFU/m<jats:sup>3</jats:sup>), with no significant difference in airborne endotoxin levels between the chambers. Our results showed that the SAEW spray air purifier could effectively remove airborne bacteria without increasing airborne endotoxin levels within a 30-minute operational period.","PeriodicalId":13578,"journal":{"name":"Indoor and Built Environment","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141884768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-30DOI: 10.1177/1420326x241268162
Li Tong, Jinchao Li, Songtao Hu, Ping Chen
The salivary immunoglobulin E (IgE) level that usually acts as an indicator of human immunity could change significantly with the air temperature. Electroencephalography (EEG) is a commonly used technique to assess the thermal responses of the human body to the environment. However, the relations between them under step-change temperatures would still need more evidence. Experiments were conducted in this study to explore the EEG–IgE relation. Three step-changed temperature conditions in the controlled environment by a climate chamber were selected in this study, under which the air temperature was suddenly transitioned from a low temperature of 15°C to higher temperatures of 18°C, 24°C and 30°C, respectively, before returning to the initial low-temperature condition. The subjective questionnaires, the EEG signals and the salivary samples from 14 subjects in these three step-changed temperature conditions were collected. Results showed that the thermal comfort voting was significantly correlated with the EEG spectral power and the IgE concentration. In addition, a significant negative correlation between the frontal lobe spectral power and the salivary IgE changes was observed. The spectral power of the frontal lobe could be used as an objective indicator to evaluate the salivary IgE levels under step-change temperature environments. This study has provided some guidance for future studies of the human immunity responses to the indoor environment in different seasons.
{"title":"Study on the relationship between EEG and salivary IgE under step-change temperature environments","authors":"Li Tong, Jinchao Li, Songtao Hu, Ping Chen","doi":"10.1177/1420326x241268162","DOIUrl":"https://doi.org/10.1177/1420326x241268162","url":null,"abstract":"The salivary immunoglobulin E (IgE) level that usually acts as an indicator of human immunity could change significantly with the air temperature. Electroencephalography (EEG) is a commonly used technique to assess the thermal responses of the human body to the environment. However, the relations between them under step-change temperatures would still need more evidence. Experiments were conducted in this study to explore the EEG–IgE relation. Three step-changed temperature conditions in the controlled environment by a climate chamber were selected in this study, under which the air temperature was suddenly transitioned from a low temperature of 15°C to higher temperatures of 18°C, 24°C and 30°C, respectively, before returning to the initial low-temperature condition. The subjective questionnaires, the EEG signals and the salivary samples from 14 subjects in these three step-changed temperature conditions were collected. Results showed that the thermal comfort voting was significantly correlated with the EEG spectral power and the IgE concentration. In addition, a significant negative correlation between the frontal lobe spectral power and the salivary IgE changes was observed. The spectral power of the frontal lobe could be used as an objective indicator to evaluate the salivary IgE levels under step-change temperature environments. This study has provided some guidance for future studies of the human immunity responses to the indoor environment in different seasons.","PeriodicalId":13578,"journal":{"name":"Indoor and Built Environment","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141870375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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