## 1 Introduction  
With the rapid development of urbanization, the demand for office space in cities has significantly increased. The quality of the acoustic environment in the office space becomes a critical factor affecting the work performance and well-being of the workers [1]. Noise has been proven to have considerable negative effects on workers' moods, efficiency, and even long-term health [2; 3]. Numerous field measurements and questionnaire surveys have described the objective characteristics of and subjective responses to noise in office environments. Most field measurements have primarily focused on sound level indicators, including the A-weighted equivalent sound level (L\({}_{\text{Aeq}}\)) and percentile levels (L\({}_{10}\), L\({}_{50}\), L\({}_{00}\), etc. ), to describe the spatial and temporal characteristics of background noise levels [4; 5]. It has been found that there is a significant variation in noise levels which is highly dependent on the office type [4; 6]. In enclosed offices, where employees are separated by walls or panels, have resulted in a relatively low noise level [7; 8; 9]. In open-plan offices, as the volume of space and the number of workers tend to be higher, more noise sources have been identified, leading to higher noise levels [10; 11]. In addition to the noise level, the noise source has been proven to be a crucial factor in determining how people perceive the sound environment [12]. A questionnaire survey is the most common method to document the response of workers to various sound sources. As reported, human-generated sounds (speech, footsteps, etc. ), mechanical sounds (keyboard, printer, ventilation, etc. ), and music have been identified as the primary interior sound sources in office spaces [13; 14; 15]. The telephone ringing and speech noise have been reported as the most frequently perceived and the most annoying noise sources, respectively [9; 16; 17; 18]. Meanwhile, continuous noises, such as air-conditioner noise, are generally considered to cause little annoyance. Traffic sounds, construction sounds, and natural sounds have been reported as the most common exterior sound sources [19]. Among these sound sources, road traffic noise has been suggested to be one of the major sources of disturbance to daily work activities [20; 21]. In most previous studies, people have been found to be more frequently annoyed by interior noises than traffic noises when comparing different noise sources [15; 19]. Due to the building envelope, the exterior noise level is significantly lower than speech noise, especially in open-plan offices. Therefore, speech noise is commonly identified as the most influential noise source. However, for enclosed offices and offices located near traffic lines, the annoyance caused by traffic noise might increase due to the rise in traffic noise levels or the reduction in noise level of other noise sources [22]. Based on a field survey, it was reported that 81% of workers near the major streets were annoyed by traffic sounds [20]. [PERSON] et al. [23] reported that people were more annoyed by exterior noises than interior noises in high-rise offices, especially in areas with a heavy road traffic flow. For individuals who work from home, traffic noise has been reported as the second most annoying source of noise [24]. Measuring the sound level of each sound source in a field survey is very challenging. Therefore, disagreements in the effects of noise sources could be found in the existing studies. In contrast to field surveys, laboratory experiments are commonly used to measure how subjects respond to controlled stimuli. A laboratory experiment was conducted to compare the restorative effects of various sound sources in an office environment [25]. It was found that the negative impact of traffic noise is significantly greater than that associated with air conditioners at the same noise level. [PERSON] et al. [26] compared the effects of traffic noise and air-conditioning noise on visual cognitive performance in office spaces. [PERSON] et al.