Indoor environmental quality (IEQ) has significant impacts on office occupants' productivity and these impacts differ according to the type of office. The present study focuses on a special type of ...open-plan offices, university open-plan research offices (UOROs), and aims to study how the IEQ of this type of offices affects the occupants' productivity. A four-part IEQ assessment framework for the University Open-plan Research Office (UORO) is first proposed. Then the investigation is conducted based on survey responses collected from 231 people who are working in UOROs from 19 universities in China. The analysis results show a clear picture of (1) how the office productivity is affected by the five key IEQ aspects (layout, air quality, thermal comfort, lighting and acoustic environment), (2) how these five key IEQ aspects are affected by their corresponding sub-factors, such as conversation noise, and (3) how occupants' perception of sub-factors are affected by individual factors, such as occupant demographics and work activity. The results also emphasize the quality of acoustic environment has the greatest influence on the occupants' productivity in UOROs and imply occupants working in UOROs have higher requirements for acoustic environment than in other common types of open-plan offices. Based on the analysis, a decision-making strategy is also presented for the evaluation and improvement of the IEQ of UOROs.
•The impacts of indoor environmental quality (IEQ) on work productivity in university open-plan research offices (UOROs) are studied.•How the qualities of key IEQ aspects in UOROs are affected by their sub-factors are analyzed.•Individual factors, such as occupant demographics and work activity, have significant impacts on the perception of IEQ in UOROs.•Occupants working in UOROs could have higher requirements for acoustic environment than in general open-plan offices.•A decision-making strategy for UORO's IEQ evaluation and improvement is also proposed.
Owing to the COVID-19 pandemic, working from home promotes the importance of indoor environment qualities. With the settings and functions of home offices, an experiment was carried out to determine ...the interaction effects between indoor plants and traffic noise levels (TNLs) on the performance and environmental evaluations of English reading comprehension tasks (ERCTs) and the performance of short-term breaks. A sample of 22 Chinese university students (12 males and 10 females) took part in the experiment. Two visual conditions (with and without plants) and five TNLs (i.e., 35, 45, 50, 55, and 60 dBA TNL) were included. Participants’ accuracy rates, eye movements, mental workload, and feelings about the environment were collected. The mental fatigue recovery (MFR), visual fatigue recovery (VFR), anxiety recovery (AR), and unfriendly recovery (UR) were measured for the analysis of a 5-min short-term break. The results demonstrate (1) plants have significant effects on ERCTs and short-term breaks, especially at 45 and 50 dBA TNL; (2) the effects of TNLs on ERCTs’ eye movements and work environment satisfaction differ by the presence of plants, e.g., the average pupil diameter (APD), lighting and layout satisfaction; (3) The effects of indoor plants on ERCT differ by the range of TNLs. In conclusion, indoor plants are beneficial to home workers engaged in ERCT when TNL does not exceed 50 dBA. The current data highlight the importance of audio-visual interaction in home offices and provide insights into the interaction mechanism between indoor plants and traffic noise.
•Effects of masking sound and SNR on work performance in Chinese open-plan offices.•Both objective and subjective performances are tested under 14 acoustic conditions.•Both masking sound type and SNR ...can have significant effects on work performance.•Water sound with SNR of 2.4 dB is the best condition among 12 masking conditions.•The effects of masking sound differs by occupants’ individual factors.
A laboratory experiment has been carried out in this paper to study the effects of masking sound and signal-to-noise ratio (SNR) on occupants’ objective performance and perceived sound environmental quality in Chinese open-plan offices. The serial recall task performance and subject perceptions of 30 participants were tested under 14 different acoustic conditions, including “Quiet” (the condition without neither masking sound nor speech noise), “Speech_only” (the condition without masking sound but with speech noise), and 12 masking sound conditions. In these masking sound conditions, 4 masking sources (speech-like pink noise, air-conditioning noise, spring water sound and babble) were used and each source was given under 3 levels of SNR (i.e., small (−6.6 to −5.5 dB), medium (−3.0 to −2.3 dB) and large (4.4–4.8 dB) levels). The results demonstrate: (1) the effects of masking sound environment on occupants’ objective performance and perceived sound environmental quality (including acoustic satisfaction, perceived disturbance and subjective workload) can significantly differ by masking source and SNR, (2) spring water sound at medium SNR (SNR = −2.4 dB) is the best condition among the tested 12 masking sound environments, and (3) the effects of masking sound on occupants may differ by their individual factors, such as gender, educational level and noise sensitivity. According to the authors’ knowledge, this study is the first attempt to study the effects of masking sound and SNR on work performance in Chinese-language open-plan office environments. The findings can be used as a reference for the acoustic research and design of Chinese open-plan offices.
Speech noise can reduce occupants' work performance in open-plan offices. Some models have been created to predict the effect of speech of different intelligibility on work performance. However, few ...of them consider the effects of speech intelligibility in Chinese environments. This study aims to develop a model that evaluates how much work performance is decreased by speech noise with different intelligibility in Chinese open-plan offices. A laboratory experiment has been conducted in this paper to determine the effects of different speech intelligibility on occupants' objective performance of the serial recall task and perceived speech disturbance in Chinese open-plan offices. Then, a prediction model was developed by analyzing the data from this experiment and two previous studies. These two studies researched the effects of the Speech Transmission Index (STI, an objective parameter of speech intelligibility) on the serial recall performance in Chinese environments. According to the prediction model of serial recall performance in Chinese environments, performance decrease occurs within the STI range of 0.31–0.47. The comparison of curves between STI and DP with previous studies shows that the STI range for serial recall performance variation in Chinese environments is narrower than in non-Chinese language environments. Furthermore, the DP average change rate of serial recall tasks in Chinese environments is not less compared to non-Chinese environments, although the effect of speech noise on serial recall performance is lower in the Chinese environment.
•The effect of STI on serial recall performance in Chinese environments is studied.•A STI-DP model for Chinese open-plan offices (COPOs) is first developed.•Occupants' serial recall performance decreases with the STI in COPOs.•Work performance decrease occurs within the STI range of 0.31–0.47 in COPOs.•The STI range in Chinese environments is narrower than in non-Chinese environments.
•The effects of noise level and speech privacy in Chinese LOPOs and MOPOs are studied.•Both acoustic measurement and subjective rating of LOPOs and MOPOs are compared.•The spatial density of ...workstations strongly correlates with D2,S, Lp,A,S,4m and rC.•MOPO employees showed a higher acoustic satisfaction than employees in LOPOs.•Speech privacy significantly correlates with work productivity in LOPOs.
Few studies have investigated whether employees have different acoustic demands for various types of open-plan offices (OPOs), which can be subdivided into small, medium-sized and large OPOs depending on the number of employees sharing an office. In this study, an investigation of acoustic environment is carried out in 16 OPOs, aiming to 1) study how the design parameters of OPOs affect indoor acoustic environments, and 2) explore whether occupants’ demands of acoustic environments are different between large open-plan offices (LOPOs) and medium-sized open-plan offices (MOPOs). Both objective measurement and subjective evaluation results that relate to the key aspects of the acoustic environment (noise level and speech privacy) are collected from 7 LOPOs and 9 MOPOs in China. The analysed results found that OPOs with the lower spatial density of workstations or higher storey height have the higher spatial decay rate of speech (D2,S), lower speech level at 4 m distance (Lp,A,S,4m) and shorter comfort distance (rC). The perceived noise level has the greatest influence on employees' acoustic satisfaction, and speech interference on employees' re-concentration is the main acoustic reason leading to work productivity decrease. In terms of the differences in acoustic environment between LOPOs and MOPOs, MOPO employees have higher acoustic satisfaction and lower disturbance levels of speech noises. Perceived speech privacy is a significant acoustic factor affecting work productivity in LOPOs, while it is not in MOPOs.
•The effects of 4 acoustic quality levels in open-plan offices (OPOs) were studied.•The impact of acoustic conditions at 2 positions of all office scenes was compared.•The validity of acoustic ...classification criteria in ISO 3382–3:2022 was confirmed.•Moving away from speakers is beneficial for occupants with poor OPO acoustics.
A laboratory experiment was performed to explore the effects of acoustic quality levels on work performance and perceptions in open-plan offices. The accuracy rate of the serial recall task and the reported perceptions of the 41 participants were tested at two receiving positions in four office scenarios. According to the revised international standard for measuring room acoustic parameters in open-plan offices, ISO 3382–3:2022, the room acoustic qualities of the four office scenarios were classified into four levels (good, high-medium, low-medium, and poor). The results confirm the validity of the acoustic classification criteria in ISO 3382–3:2022 and highlight that people working in offices with good acoustic quality have significantly higher work performance and acoustic satisfaction than those working in offices with poor acoustic quality. Moreover, comparisons of objective and subjective results between the two receiving positions imply that maintaining a greater distance from people speaking improves work performance and acoustic satisfaction in offices with poor acoustic quality. However, this improvement is insignificant when working in offices with good acoustic quality.
•Effects of STI on work performance in 2 RT conditions in Chinese open-plan offices.•The effect of 2 RTs on acoustic perceptions under the same STI condition is studied.•A long RT condition can ...reduce the negative effects of speech at the STI of 0.42.•Work performance decrease with the increase in STI in the absorbing environment.•Female subjects were more satisfied with acoustic environment than males.
Speech intelligibility is an essential index for evaluating acoustic performance in open-plan offices. Both speech-to-noise ratio (SNR) and reverberation time (RT) are critical parameters for determining the Speech Transmission Index (STI). STI is an important parameter for the objective prediction of speech intelligibility. Many studies explored the effects of speech intelligibility on work performance and acoustic environmental perceptions in open-plan offices by changing the SNR to obtain various STI conditions. However, few studies research how RT affects speech intelligibility and then influences work performance and perceptions of acoustic environments in open-plan offices. This study conducted a laboratory experiment to identify the changing trends of work performance and acoustic environment perceptions with the increase in STI under different RT conditions and to explore how room RT affects work performance and perceptions of the acoustic environment under the same STI condition. The acoustic conditions tested in this study varied in speech intelligibility (STI of 0.21, 0.42, and 0.61) and reverberation time (RT of 0.4 s and 1.4 s). The main outcome of this study is that occupants have less mental workload, faster task completion speed, and higher acoustic adaptability in a long RT environment compared to a short RT environment at an STI of 0.42. Furthermore, the data show a decreased work performance and an increased speech disturbance with the increase in STI in the short RT environment, while that trend was not observed in the long RT environment. The effects of STI conditions on occupants may differ by gender and noise sensitivity.
Speech Transmission Index (STI) is a critical indicator of speech intelligibility in quantitatively evaluating work efficiency in open-plan offices. Previous research has examined the ...STI-productivity relationship for simple, continuous tasks. Compared to continuous, simple tasks, interleaved complex tasks demand more effort to maintain work efficiency. However, the association of speech intelligibility with the efficiency of complex tasks remains inadequately explored. Therefore, this study investigates the impact of speech intelligibility on the productivity of interleaved scientific reading comprehension, contrasting it with productivity in continuous task modality. Thirty graduate students were recruited and exposed to irrelevant speech environments featuring speech-like pink noise as masking sound. By adjusting the sound pressure levels of speech and masking sounds, seven distinct acoustical conditions with different STI values (0.17, 0.26, 0.36, 0.45, 0.52, 0.57, and Speech_only) were created. A “Quiet” condition was also considered as a control group. Generalized Linear Mixed Models were utilized to analyze the relationships between speech intelligibility, task modality, and objective and subjective outcomes. The study found that, when the STI lies within the range of 0.26–0.45, employees must exert more effort to maintain task efficiency and resist distractions. If task-switching is involved when the STI exceeds 0.50, research efficiency further decreases. Overall, the interruption of tasks appears to amplify the impact of speech intelligibility on research efficiency. These findings underscore the importance of considering both work modality and the acoustic condition in optimizing cognitive performance and the overall user experience.
•Interleaved-task has lower perceived performance under quiet condition.•Higher speech intelligibility impacts performance negatively.•Interleaved-task modality amplifies impacts of irrelevant speech on efficiency.•Task switching shows varied impacts at different speech transmission indexes.•Task modality and speech transmission index interaction affects satisfaction.
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•The shale gas resource potential of the Longmaxi Formation was evaluated by using mud gas isotope logging technology.•The reservoir properties of shale were evaluated based on gas ...isotope fractionation effects.•The shale gas in the Changning area belongs to late kerogen cracking gas.•The lower part of the Longmaxi Formation has a better shale gas exploration potential.
The Longmaxi Formation in the Sichuan Basin is one of the most important shale gas producing formations in China. Previous studies of shale gas were mostly carried out on based on laboratory analyses and did not provide effective guidelines for shale gas exploration. In this paper, we present a large amount of carbon isotopic data from mud gas isotope logging and rock-cutting headspace gas in wellsites. The δ13C1 values showed a significant decrease at the bottom of the Longmaxi Formation. The δ13C1 and δ13C2 values in the Changning area were observed to be heavier than those in the Weiyuan and Jiaoshiba areas. The second half of the N216H27-3 horizontal well had obvious outgassing and carbon isotope fractionation effects. This indicates that the bottom of the Longmaxi Formation has better shale gas exploration potential. The shale gas of the Longmaxi Formation in the Changning area belongs to late kerogen cracking gas, where exploration prospects are poorer than those in the Weiyuan and Jiaoshiba areas. There were more oil cracking gas resources and better reservoir conditions at the end of the N216H27-3 horizontal well; therefore, drilling should be continued at this site.
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