Continuous A-weighted Sound Pressure Level Research Articles

Effects of acoustic environment on sleep and mental health in residential regions near railways

Noise is an important environmental risk factor for physical and mental health. Furthermore, long-term noise exposure is burdensome for the mind and body and has become a serious problem. Rail transportation is one of the main methods used to transport goods in China; however, the noise and vibrations generated by freight trains have serious impacts on residents in nearby regions. To further investigate the relationship between railway noise and road noise exposure and changes in sleep duration and mental health scores, a field study in Harbin, China, was conducted and a health risk prediction model was constructed. The results showed that for every 1 dB increase in the Equivalent continuous A-weighted sound pressure level (LAeq), the percentage of deep sleep among residents living near the railway decreased by 0.2 %. Although residents near the railway reported similar sleep evaluations compared to those living farther away, they exhibited poorer mental health. Cox risk modeling indicates that the risk of mental health problems is approximately three times higher for those living near the railway. These findings potentially provide benefits in developing strategies to reduce the risk of mental illness for people residing near railways.

Forecasting an urban sound model using space syntax theory in three different urban patterns in Egypt

The objective of this study is to investigate an acoustic environment based on spatial configurations. To achieve this objective, two types of data were utilized. First, the urban acoustic data was collected from 96 measurements based on equivalent continuous A-weighted sound pressure levels across three different urban areas in Cairo, Egypt, during weekends and at night. The data was plotted on a contour map in an effort to investigate their distribution in the urban area. Secondly, the data was collected using DepthMapX software, and in this way, spatial analysis was produced with diverse spatial attributes. Moreover, on-site observations of pedestrian and traffic rates were made, and land use distribution was observed.Statistical analysis was also conducted using the Statistical Package for Social Sciences (SPSS). Our statistical analysis showed that the value of sound pressure level (LAeq) is greatly influenced by spatial attributes in highly accessible spatial configurations, with Normalized Angular Integration (NAIN) being the most accurate predictor of sound pressure level. Our findings also verified the existence of a high correlation between commercial and mixed land uses and (LAeq).Additionally, this study revealed that the urban sound model can predict sound pressure level (LAeq) in an urban setting. This dataset functions as a valuable resource for future research, urban designers, and policymakers who are addressing sustainable issues pertaining to soundscape, noise pollution, and urban planning.

Variations in sound environment in an urban apartment building: A case study during and after the COVID-19 lockdown

Quiet communities, which are encouraged to maintain a harmonious and tranquil urban living environment, have attracted increasing attention in designing method in recent years. The relevant residential standards specify quiet thresholds with regard to noise pollution issues. However, the variation in height across floors of high-rise buildings and variation with time in sound environments have not been examined in detail. The city of Shanghai experienced a city-wide lockdown to control the spread of COVID-19, showing evidence of quietness and a significant reduction in anthropogenic noise. Here, we conducted noise monitoring in a 14-storey apartment building that was surrounded and shielded by other buildings in a typical urban community during and after the lockdown. The mean value of all 14 floors of equivalent continuous A-weighted sound pressure level (LAeq,T) after lockdown was systematically greater than that during lockdown, with differences of 3.6 and 3.1 dB during the daytime and night-time periods, respectively. We suggest that in practice, it is useful to consider the specific floor or time of day.

Sound Environment during Dental Treatment in Relation to COVID-19 Pandemic

This study delves into the acoustic environment within dental clinics, particularly focusing on the impact of extraoral suction devices employed for infection control amid the COVID-19 pandemic. The research encompasses a comprehensive investigation, including a questionnaire survey of dental professionals, sound level measurements at suction device openings, acoustic imaging, and a detailed analysis of sound levels and their spectral characteristics during dental procedures. Additionally, ambient sound levels within clinical settings were monitored over two consecutive days. The findings reveal notable observations. Dental professionals expressed concerns regarding increased sound levels and associated distress caused by extraoral suction device operation. Objective measurements identified varying A-weighted sound pressure levels ranging from 86.0 dB to 96.7 dB at suction device openings, highlighting elevated sound pressure levels and a wide frequency range, especially in the vicinity of both the dentist and the patient’s facial area during dental aerosol procedures. On the other hand, for the entire clinical room, the equivalent continuous A-weighted sound pressure level during the consultation hours was not considered problematic. In light of these findings, it becomes evident that there is a pressing necessity to refine the acoustic characteristics of extraoral suction devices to foster a more accommodating acoustic environment for both patients and dental healthcare professionals within dental clinics.

Effects of Audio-Visual Environmental Factors on Emotion Perception of Campus Walking Spaces in Northeastern China

In the context of urban sustainable development and the creation of pedestrian-friendly campus environments, optimizing campus walking spaces has emerged as a central focus in urban planning research. Presently, research in pedestrian environments predominantly adopts a macroscopic perspective, offering limited insights into pedestrians’ subjective experiences and emotional perceptions at a micro level. Therefore, this study conducted on-site experiments in 21 walking spaces across three campuses, utilizing image semantic analysis, multifunctional sound level meter, wearable electrocardiography devices, and the Profile of Mood States (POMS) to collect data separately on audio-visual environmental factors and pedestrians’ emotional states. This study’s findings revealed significant correlations (p < 0.01) among factors such as the Green Visual Index, Spatial Enclosure Index, Sky Visibility Index, Spatial feasibility Index, and Equivalent Continuous A-weighted Sound Pressure Level with physiological and psychological alterations in pedestrians’ emotions. Additionally, the various proportions of audio-visual environmental factors also exerted significant influences on emotions (p < 0.05). The relevant conclusions can provide a reference for optimizing the audio-visual environment of walking space and promoting the sustainable development of the campus. In future research, the effects of audio-visual environments on both emotional and physiological indicators, as well as subjective evaluations, can be explored further.

Noise Exposure and Job Stress – a Structural Equation Model in Textile Industries

Noise exposure is one of the most important physical agents in the workplace which can induce job stress in several ways. The aim of this study was to model the interactions between independent and mediating variables and job stress using structural equation modeling. In this study, Weinstein’s noise sensitivity scale, noise annoyance questionnaire, Health and Safety Executive (HSE) job stress questionnaire and job satisfaction scale were used. To assess worker’s noise exposure, the 8-hours equivalent continuous A-weighted sound pressure level (LAeq;8 h), was measured based on ISO 9612 (2009). To achieve the aims of study, the structural equation model was run using R software 3.4.1 and Cytoscape software 3.6.0. Based on the results, while there was a direct positive correlation of noise exposure on total job stress, there were also indirect positive effects through job satisfaction and noise sensitivity as mediator variables. Using hearing protective devices negatively affected total job stress through a direct pathway and an indirect pathway when job satisfaction was a mediator variable. Regarding the total effect of noise exposure and using hearing protection devices on job stress subscales, it can be concluded that noise exposure and using hearing protection devices had greatest effect on colleagues support and demand, respectively. It can be concluded that noise exposure and lack of hearing protective devices have a significant positive effect on job stress among workers of a textile industry. In addition to the direct effect, this factor can induce job stress through noise sensitivity, job satisfaction and noise annoyance. Therefore, measures which can decrease any of the mentioned factors, also can alleviate job stress.

Smart mobility procedure for road traffic noise dynamic estimation by video analysis

Road Traffic Noise is a major concern in Europe, with more than 20% of people exposed to harmful noise levels. Efficient monitoring and assessment of the sound levels in critical areas are crucial to support decision strategies to control/reduce noise exposure. However, continuous and long-time ranged spatio-temporal measurements require high-cost equipment and maintenance duties. Therefore, this paper aims to develop a cost-efficient smart mobility procedure for the estimation of traffic noise levels based on roadside video images. The developed procedure involves an algorithm that extracts traffic volumes, identifies vehicle classes, estimates each vehicle’s speed from video recordings, and a noise assessment component using dynamic microscopic models. These latter are based on existing Noise Emission Models – NEMs, for the assessment of the source sound power levels, coupled with a sound propagation model able to consider each on-road vehicle speed as input and evaluate the equivalent continuous A-weighted sound pressure levels. The developed approach is characterized by a modular structure that easily allows to replace NEMs and/or incorporate extra variables in the sound propagation model. The procedure is tested on a rural road of a medium-sized city, under different levels of service, and results show that the errors concerning the noise estimations are below 1 dBA, revealing high accuracy.

Sound environment in an urban apartment building during and after the COVID-19 lockdown.

Quiet areas, such as quiet communities, are encouraged to maintain a harmonious and peaceful urban living environment, and the design approach has drawn increasing attention in recent years. Related residential standards define the thresholds of quietness concerning noise pollution problems. However, the variations in height across floors of high-rise buildings and time in sound environments have not been detailed. The city of Shanghai experienced a citywide lockdown to contain the spread of COVID-19 showing the evidence of quietness with marked reductions in anthropogenic noise. Here, we conducted noise monitoring in a 14-story apartment building surrounded and shielded by other buildings in a typical urban community during and after lockdown. The mean value of the equivalent continuous A-weighted sound pressure level (L Aeq ) of all 14 floors after lockdown was higher than that during lockdown, and the differences were 3.6 and 3.1 dB during the daytime and night-time periods, respectively. The L Aeq values at low heights were slightly lower than those at high heights during and after lockdown. The variations due to the different heights were not great. However, the change tendency from the ground to the top floors was similar and correlated during and after lockdown. The difference between the maximum and minimum values of the floors was 3 dB during the daytime period and 4.5 to 5.1 dB during the night-time period. The day equivalent continuous A-weighted sound pressure level (L day ) and night equivalent continuous A-weighted sound pressure level (L night ) at the middle building height increased 4.0 and 1.3 dB, respectively, after lockdown. The L Aeq change tendency during a daily cycle during and after lockdown was similar and highly correlated. The differences in the frequency characteristics of noise level were larger within the 63 to 2,000 Hz range. We suggest that the building represents a typical quiet living condition in high-density habitats in China. Notably, the difference is approximately 3 to 4 dB, and the patterns of variation in height and time are similar between the absence and limited presence of anthropogenic noise. In practice, it would be useful to consider specific floor level or time of day.

A study on the control indices and emission limits of substation noise

Equivalent continuous A-weighted sound pressure level (LAeq) underestimates the influence of low-frequency components of substation noise, so it is necessary to optimise control indices and emission limits of substation noise. To this end, 148 noise samples from 110 kV–1000 kV substations were selected. 280 subjects were randomly recruited for listening tests in which the 11-point numerical scale specified by ISO 15666-2021 was used. The mean noise annoyance (Am) of each noise sample was obtained to establish the LAeq-Am model of substation noise. Meanwhile, the LAeq-LFNR model was established based on the low-frequency noise rating number (LFNR) proposed by Broner. Based on these models, the LFNR corresponding to the limit of LAeq could be determined. The limit of sound pressure level of substation noise was proposed at each 1/1 octave band from 31.5 Hz to 500 Hz and the limit-exceeding ratio for the existing substations noise of China was analyzed. Results showed that Am of 500 kV–1000 kV substation noise was 1.0 higher than that of 110 kV–220 kV substation noise on average when LAeq was 25 dBA–80 dBA. LAeq of the latter were 6.1 dBA higher than that of the former on average when Am was 1–10. It was estimated that utmost 20 % of substations need further to take noise control measures in order to meet the limit suggested by this study in China. Binding with the limit of LAeq, the limit of sound pressure level at each octave band proposed according to equal noise annoyance can better evaluate the influence of substation noise.

Sound prediction based on footstep-induced vibrations in concrete building using a convolutional neural network

Heavy-weight impact sounds caused by footsteps are a major factor that affects acoustic comfort in concrete residential buildings. An impact monitoring system that predicts sound based on vibration could be beneficial to alter the behavior of the occupant causing excessive sound, or the stored data can be used by mediators in case of disputes to identify the sound source household and assess the disturbance. This study presents a method for predicting the actual impact sound especially footstep in the rooms of buildings. A convolutional neural network (CNN) was used as the prediction model and the signal from vibration sensors placed in the floors and walls of the room as input data. We experimentally collected a dataset and compared its performance according to the location of the vibration sensors and the resolution of the short-time Fourier transform (STFT) feature, which represents footstep-induced vibrations. The highest accuracy was achieved when the vibration signals of both the wall and floor slab were used simultaneously in the CNN model, with the frequency resolution of the STFT of 10 Hz and the window frame offset of 50 ms. The equivalent continuous A-weighted sound pressure level for 2 s was predicted with 0.99 dB as the mean absolute error, and the value of the coefficient of determination was 0.95. The performance of sound pressure level in the 63 and 500 Hz frequency bands achieved mean absolute error of 1.63–2.22 dB.

Study on Subjective Evaluation of Acoustic Environment in Urban Open Space Based on "Effective Characteristics".

With the continuous expansion of urban scale with dense population and traffic and the gradual improvement of residents’ requirements for environmental quality, the traditional evaluation method relying on acoustic energy is not enough to reflect the feelings of urban crowds about acoustic environment quality. The acoustic environment quality evaluation method based on human subjective perception has gradually become one of the research focuses in the field of environmental noise control. In recent years, various subjective and objective acoustic characteristic parameters have been introduced into the study of acoustic environment assessment in the global literature. However, the extraction of “effective characteristics” from a large number of physical and psychoacoustic characteristics contained in acoustic signals and the creation of a scientific and efficient subjective evaluation model have always been key technical problems in the field of acoustic environment evaluation. Based on subjective human perceptions, the overall acoustic environment quality evaluation of urban open spaces is studied in this paper. Based on the “effective characteristic” parameters and the subjective characteristic proposed in the previous research, including equivalent continuous A-weighted sound pressure level (LA), the difference between median noise and ambient background noise (L50 − L90), Sharpness (Sh), as well as satisfaction (Sat), the multivariable linear regression algorithm is used to further study the intrinsic correlation between the proposed “effective characteristics” and subjective perception. Then, a satisfaction evaluation model of the acoustic environment based on “effective characteristics” is built in this paper. Furthermore, the soundwalk evaluation experiment and the MATLAB numerical simulation experiment are carried out, which verify that the prediction accuracy of the proposed model is more than 92%, the consistency of satisfaction level is more than 88%, as well as the changes in the values of Sh and L50 − L90 have a significant impact on the satisfaction prediction of the proposed model. It shows that the proposed “effective characteristics” more comprehensively describe the quality level of the regional acoustic environment in urban open space compared with a single LA index, and the proposed acoustic environment satisfaction evaluation model based on “effective characteristics” has significant accuracy superiority and regional applicability.

Influencing Factors Identification and Prediction of Noise Annoyance-A Case Study on Substation Noise.

Noise-induced annoyance is one person’s individual adverse reaction to noise. Noise annoyance is an important basis for determining the acceptability of environmental noise exposure and for formulating environmental noise standards. It is influenced by both acoustic and non-acoustic factors. To identify non-acoustic factors significantly influencing noise annoyance, 40 noise samples with a loudness level of 60–90 phon from 500–1000 kV substations were selected in this study. A total of 246 subjects were recruited randomly. Using the assessment scale of noise annoyance specified by ISO 15666-2021, listening tests were conducted. Meanwhile, basic information and noise sensitivity of each subject were obtained through a questionnaire and the Weinstein’s noise sensitivity scale. Based on the five non-acoustic indices which were identified in this study and had a significant influence on noise annoyance, a prediction model of annoyance from substation noise was proposed by a stepwise regression. Results showed that the influence weight of acoustic indices in the model accounted for 80% in which the equivalent continuous A-weighted sound pressure level and the sound pressure level above 1/1 octave band of 125 Hz were 65% and 15%, respectively. The influence weight of non-acoustic indices entering the model was 20% in which age, education level, noise sensitivity, income, and noisy degree in the workplace were 8%, 2%, 4%, 4%, and 2%, respectively. The result of this study can provide a basis for factors identification and prediction of noise annoyance.

Analysis of the Effects and Causes of Driver Horn Use on the Acoustic Environment at Urban Intersections in Taiwan

Car horns were originally installed in vehicles for safety. However, many urban areas in several countries face noise problems related to the use of car and motorbike horns. To propose measures to suppress the use of horns, relationships between horn use and factors including driver awareness and behavior, traffic environment, and the transportation system should be investigated. The present study therefore conducted surveys to grasp the current circumstances of horn use and traffic at urban intersections in Taiwan. The relationship between horn use and the traffic volume of standard-sized vehicles was found. According to an analysis of horn use during traffic signal cycles, in many cases, horns were honked after entering intersections to turn left. In particular, horns were honked when the driver waited more than 4 s for the car in front to start moving after the green light allowing left turns was turned on. An analysis of noise levels at intersections showed that the maximum noise level value (LAmax) could be reduced if vehicle horns were not used. Multiple regression analysis also indicated that LAmax values increased with the frequency of horn use. The equivalent continuous A-weighted sound pressure level (LAeq,10min) did not change with driver horn use, and increased with the traffic volume of motorcycles.

Applying kurtosis-adjusted equivalent continuous A-weighted sound pressure level to evaluate risk of occupational hearing loss associated with non-steady state noise

Applying kurtosis-adjusted equivalent continuous A-weighted sound pressure level to evaluate risk of occupational hearing loss associated with non-steady state noise

Evaluation of kurtosis on hearing loss caused by non-steady state noise in general equipment manufacturing industry

Objective: To study the effect of occupational exposure to non-steady state noise on hearing loss in the general equipment manufacturing industry, and to explore the feasibility of applying kurtosis index to evaluate hearing loss caused by non-steady state noise. Methods: A total of 233 workers exposed to non-steady state noise in 6 general equipment manufacturing enterprises were selected as the observation group, and 237 workers exposed to steady noise in 4 textile enterprises were selected as the control group between 2012 and 2018. Personal normalized continuous A-weighted sound pressure level equivalent to an 8 h-working-day (L(Aeq, 8 h)) was determined by a noise dosimeter. Cumulation noise exposure (CNE) was calculated from L(Aeq, 8 h) and related working age, and the CNE was adjusted by using noise kurtosis (CNE' after adjustment) . Meanwhile, questionnaires and hearing loss tests were performed for all subjects. The changes in the threshold of high-frequency hearing and the incidence of high-frequency hearing loss caused by noise in the two groups were compared before and after the adjustment of the kurtosis of CNE. The correlation between CNE and the incidence of high-frequency hearing loss before and after kurtosis adjustment was analyzed. Results: There was an difference between the 3000-8000 Hz hearing threshold of workers in different CNE groups (P<0.05) . logistic regression analysis showed that CNE was a risk factor of high-frequency hearing loss for workers in the observation group (OR=1.189, P<0.05) , and trend Chi-square test showed that the incidence of high-frequency hearing loss increased with CNE levels (χ(2)(trend)=34.415, P<0.05) .Before the kurtosis adjustment, in the CNE 95~<110 dB (A) ·year level group, the incidence of high-frequency hearing loss and the high-frequency hearing threshold in the observation group were significantly higher than those in the control group (P<0.05) . After kurtosis adjustment, there was no significant difference in the incidence of high-frequency hearing loss between the observation group and the control group in each level group (P>0.05) . The correlation between CNE after kurtosis adjustment and the incidence of high-frequency hearing loss was better than that before adjustment (after R(2) adjustment >before R(2) adjustment) . Conclusion: The effect of non-steady state noise on high-frequency hearing loss of workers in general equipment industry increases with the increase of CNE, and the effect of non-steady state noise on high-frequency hearing loss of workers is greater than that of steady noise. CNE' can be used to evaluate the hearing loss caused by non-steady state noise.

Effect of processing of dental drill noise on subjective impression

The sound produced by a dental air turbine handpiece (dental drill) can markedly influence the sound environment in a dental clinic, and many patients have reported that the sound of a dental drill elicits unpleasant feelings. A comfortable sound environment for patients is desirable in medical care. To identify approaches for improving the sound quality of dental drills, we need to determine systematically the effects of the physical properties of the sounds of dental drills on their impressions. We, therefore, prepared 40 sound stimuli by processing different sound levels or frequency components comprising the sounds emitted by four kinds of dental drills. This study is designed to use psychoacoustic experiments to determine the effects of dental drill sounds on subjective impressions. The analysis resulted in the following findings: the overall attenuation of each original sound stimulus by 5 dB or 10 dB had statistically significant effects and improved the unpleasant impression. Attenuation of the frequency components above 9 kHz by 10 dB also improved the impressions, relative to those for the original sound stimuli. When the prominent frequency components at approximately 6 kHz were attenuated by 10 dB, no statistically significant differences were observed between the impressions corresponding to the original and processed stimuli. The Comfort Index (CI), which consists of the equivalent continuous A-weighted sound pressure level (LAeq) and calculated sharpness, showed a good correlation with unpleasant impressions. The present findings suggest that the consideration of acoustical characteristics based on the CI is useful in reducing the sound pressure level and refining the frequency characteristics of sounds emitted by dental drills, and this can aid in the development of new dental devices to create a comfortable sound environment in dental clinics.

Experimental study to measure the transmission loss of double panel natural fibers

In this paper, the transmission loss (TL) of the natural fiber materials will be measured experimentally at one third octave band harmonic and broadband frequencies. The different natural fibers used in this study are jute fibers, kenaf fibers, banana fibers, coconut coir fibers, and hemp fibers. An acoustic soundproof cabin has been fabricated to measure the transmission loss of natural fiber material. A one-dimensional duct is placed inside the soundproof cabin. Inside the duct there is a specimen of natural fiber materials. A loudspeaker is used to generate acoustic harmonic and white noise disturbances at various frequencies. The generated acoustic sounds then passed through the double panel natural fiber specimens. A sound pressure level (SPL) meter is used to measure the noise levels inside the duct. In this paper, a double panel natural fiber material specimen is proposed for testing. The double panel specimens are a combination of two natural fiber materials. In the double panel, the two panels are made from same or different natural fibers and also air is enclosed between them. The main objective of this paper is to measure the transmission loss and equivalent continuous A-weighted sound pressure level of fiber-air-fiber type specimens so that in future these types of combinations can be used for various engineering and other applications. It is observed that the combination of jute-air-kenaf is absorbing more sound as compared to jute-air-banana fibers and hemp-air-coconut coir fibers.

Dynamic properties of peak levels of road traffic noise along a freeway

The hourly traffic volume at night is typically lighter than that during the day. However, the average speed and the rate of heavy vehicle tend to be higher at night. It is shown that the influence of the maximum A-weighted sound pressure level (LA,Fmax) is much more dominant in the night than during the day in the roadside areas of a highway. In order to predict and evaluate the traffic noise in the areas facing the road and to investigate the influence on the health effects of the residents living in such areas, it is indispensable accurately to grasp not only the equivalent continuous A-weighted sound pressure level but also the LA,Fmax and the dynamic properties of level fluctuation of noise.

Perceived Occurrences of Soundscape Influencing Pleasantness in Urban Forests: A Comparison of Broad-Leaved and Coniferous Forests

Perceived occurrences of soundscape reflect cognitive responses to perceived soundscapes. This research focuses on the relationship between perceived occurrences and pleasantness of soundscape in urban forests, and models these parameters. Soundscape information was gathered at 60 observation sites in urban forests, including perceived occurrences of soundscape (POS), pleasantness of perceived soundscape in urban forests (PSUF), and equivalent continuous A-weighted sound pressure level (LAeq). Twelve trained participants were exposed to the soundscape at each site for five minutes and filled out a questionnaire about POS and PSUF. The weight-ratio of perceived occurrences of soundscape (WPOS) was obtained from the POS. Pearson’s correlation coefficients and Stevens’ power law were conducted to test the applicability of the perceived occurrences of soundscape in psychophysical models. Results show that there is an interaction between the WPOS and PSUF in urban forests, and that psychophysical models are able to assess pleasantness of perceived soundscapes in urban forests. Findings show that pleasantness trends of geophony and biophony in broad-leaved forests and those in coniferous forests are opposite when the LAeq is increasing. Furthermore, by combining the WPOS, PSUF, and LAeq, the models were able to link the PSUF of geophony, biophony, anthrophony, and total soundscape in urban forests. Overall, results revealed that perceived occurrences of soundscape play a key role in linking the pleasantness of geophony, biophony, and anthrophony in urban forests.

Effects of combined traffic noise on the synaptic ultrastructure and expressions of p-CaMKII and NMDAR1 in the hippocampus of young SD rats.

In order to explore the effects of combined traffic noise (CTN) on learning and memory function, young Sprague-Dawley (SD) rats were exposed to CTN from highway and high-speed railway for 52days, whose day-night equivalent continuous A-weighted sound pressure level (Ldn) was 70dB(A) (corresponding sound pressure level was 80dB). The synaptic ultrastructure and the expressions of phosphorylated calcium/calmodulin-dependent protein kinase II (p-CaMKII) and N-methyl-D-aspartate receptor 1 (NMDAR1 or NR1) in the hippocampus were tested by transmission electron microscopy (TEM) and Western blot, respectively. Results showed that there was no significant difference in the synaptic ultrastructure and the expressions of p-CaMKII and NR1 in the hippocampus of young rats between the experimental group and control group. Compared with single high-speed railway noise (HSRN) with Ldn of 70dB(A), CTN had less influences on learning and memory function, which was closely related to smaller intermittency of CTN and less anxiety caused by CTN. In comparison with white noise with a sound pressure level of 80dB, CTN had less impacts on learning and memory function, which was mainly associated with CTN's smaller R-weighted sound pressure level based on rats' auditory sensitivity.