Showing 6 results for Noise
Mohsen Aliabadi, Neda Mahdavi, Maryam Farhadian, Masoud Shafie Motlagh,
Volume 1, Issue 2 (12-2013)
Abstract
Introduction: Noise pollution cause mental fatigue, concentration disturbance and learning loss in students during the training activities. This study aims to evaluate Noise pollution and the level of acoustical comfort in typical classrooms, and present treatment methods for improving acoustic comfort.
Method: In cross sectional study, twenty classrooms in the seven faculty of Hamadan University of medical sciences, were studied using questionnaire with reliability coefficient equal to 0.8 was completed among 413 students. Measurement of noise level was performed using sound level meter (model TES-1358) according ANSI S12.6 in classrooms.
Result : The results showed the background noise level and outdoor noise level were equal 46.97 ± 3 dB(A), and 57.16 ± 4.8 dB(A) , respectively. The background noise was higher than the recommended limit equal to 45 dB(A) (P<0.01). The construction activities are most important annoying factor and concentration disturbance are most complication of noise. Signal to noise ratio within the classroom was 13.14±3.54 dB (A), which was inappropriate compared with the recommended limit 15 dB (A) (P<0.01). The difference in speech intelligibility at various levels of signal to noise ratio was significant (p<0.05).
Conclusion: The results confirmed the studied classrooms haven’t acceptable acoustic conditions and background noise level was affected by outdoor noise. In regard to confirmation of the effects of noise on the student attention, the acoustic interventions is must be considered.
Azam Biabani, Mohsen Aliabadi, Rostam Golmohammadi,
Volume 4, Issue 2 (10-2016)
Abstract
Introduction: Nominal noise reduction rate of the earmuff manufacturers can be different compared with the actual attenuation rate. The present study aimed to determine the actual noise reduction rate of common hearing protection devices using microphone in real ear method.
Materials and Methods: In this study, five brands of common earmuffs used in Iranian industries were investigated on 30 subjects under laboratory conditions. Noise reduction rates of earmuffs were measured based on the ISO 11904 standard, microphone in real ear method, using noise dosimeter (SVANTEK, SV 102 model) equipped with a microphone SV 25 model. The earmuffs comfort was also assessed by the developed questionnaire.
Results: The results showed that the real noise reduction rates of the earmuffs were between 49% to 86% of nominal reduction rates. Moreover, the actual insertion losses were much negligible at low noise frequencies. The performances of earmuffs based on manufacturers were not statistically different (Pv> 0.05). Based on subjects’ comfort scores, comfort of ear muffs were within the acceptable range. The noise reduction rates of the different earmuffs of each model were not statistically different as well (Pv > 0.05).
Conclusions: Irregular use of earmuff can reduce the real attenuation of earmuff to lower than the minimum rate acquired in this study. Proper training and adequate supervision on proper use of earmuff can affect earmuff fitting along with increasing of real noise attenuation.
Mostafa Rahmiani-Iranshahi, Mohsen Aliabadi, R Rostam Golmohamadi, Alireza Soltanian, Mohammad Babamiri,
Volume 9, Issue 1 (4-2021)
Abstract
Background and Objectives: Noise is known as an intruder in job environments and has non-hearing effects. The impact of noise on cognitive functions depends on the type of noise and the dose of noise exposure. This study aims to investigate the effect of noise exposure on cognitive functions and sleep quality.
Methods: This descriptive-analytical cross-sectional study was performed on 169 workers in three metal, chemical, and food industries in Hamedan in 1399. A continuous performance test was used to evaluate cognitive functions. The Petersburg questionnaire assessed participant's sleep quality. Using SVAN 971 analyzer and TES dosimeter, the level of noise exposure and the dominant frequency was measured. Data were also analyzed using linear and multiple regression in SPSS software (version 16).
Results: There is a significant difference in the level of noise exposure with changes in cognitive functions and sleep quality in the present study (P<0.001). The results of linear regression showed that there is a significant relationship between cognitive function and the level of exposure to sound (P<0.001). After identifying and determining the input variables, using multiple regression, an appropriate model was developed to predict sleep quality and sustained attention in the face of noise.
Conclusion: Based on the results of this study, predictive models with the appropriate coefficient of determination can be good models for assessing the quality of sleep and attention of people in the face of noise, which can be implemented and measured in a shorter time.
Solmaz Tabe Afshar, Sahar Toofan, Arash Saghafi Asl,
Volume 10, Issue 2 (9-2022)
Abstract
Objectives: Undoubtfuly, people spend a significant portion of their time in workplaces. Many factors affect the health and well-being of employees. The present study aimed to identify the architectural problems of the environment by examining the symptoms of Sick Building Syndrome and ranking the parameters influenced by five physical factors (thermal comfort, noise, lighting, layout-ergonomics and decoration).
Methods: The present descriptive-analytical research was carried out in the summer of 2021. The statistical population included 52 employees of Urmia Engineering Organization Building which is based on Morgan's table and a sample size consisting 46 people was randomly selected. The required data were collected through a questionnaire and analyzed using descriptive statistics (frequency, percentage, mean and standard deviation) and Friedman test.
Results: Considering the average ranks, symptoms of fatigue (4.47), muscle pain (5.47), headache (5.87), high stress (6.14) and poor concentration (7.45), along with some defined parameters for each of the factors, including overcrowding and lack of speech privacy (78.12%), the noise of people's conversation (62.93%), improper workplace temperature in winter (58.59%) and summer (49.91%), inappropriate placement of uses and allocation of inadequate space for people and equipment (49.91%) played the most significant role.
Conclusion: The results indicated that the inefficient design of the environment and non-observance of ergonomic principles as a result of unprincipled renovations regardless of the nature of the work and its requirements, inappropriate placement of uses, the non-standard distribution of employees in an inflexible environment, lack of speech privacy and crowding were identified as the most important causes of the symptoms.
Rasoul Hemmatjo, Abolfazl Ghahramani, Mansour Mahmoodaghbash,
Volume 12, Issue 4 (2-2025)
Abstract
Objectives: Numerous factors such as job types and conditions, work organizations, and individual characteristics affect work ability of the workers. Furthermore, occupational stress is not solely influenced by individual characteristics; a stressful work environment is also a significant source of stress. Noise has been recognized as one of the major occupational hazards that adversely affects work condition in many industries. In the present study, the association of noise exposure with occupational stress and work ability of the workers in a food processing plant was investigated.
Methods: This descriptive-analytic study was performed on 142 workers of a food processing plant in various work groups. The OSIPOW questionnaire results were utilized to measure occupational stress and the work ability of the workers was determined by Work Ability Index (WAI) questionnaire. Noise exposure of the workers was calculated as a measure of 8-hour time weighted average. The association between noise exposure and work ability was analyzed using Pearson and Spearman correlation tests. Multiple regression test was utilized to analyze the simultaneous effect of variables. Moreover, one-way analysis of variance (one-way ANOVA) was used to analyze the mean difference of independent variables.
Results: The findings demonstrated a significant positive association between noise exposure and stress level across various work groups (P<0.001). Furthermore, a significant negative relationship can be found between noise exposure and work ability of the workers (P<0.001). A simultaneous analysis of variables influencing occupational stress and WAI showed that noise had the most effect. Although occupational stress levels were not significantly different across working groups, mean difference of WAI was significant.
Conclusion: Based on the obtained findings, higher levels of noise exposure may contribute to increased occupational stress and decreased work ability among workers.
Ali Sobhani Dargah, Mohsen Aliabadi, Rostam Golmohamadi, Maryam Farhadian, Mohamad Babamiri, Shiva Mohammadjani Kumeleh,
Volume 12, Issue 4 (2-2025)
Abstract
Objectives: The present study aimed to investigate the effect of tonal noise and background speech on neurophysiological parameters and noise annoyance based on personality characteristics.
Methods: In this experimental study, 25 male students were exposed to four scenarios of tonal noise, irrelevant speech, and broadband noise as a reference in a simulated laboratory environment. The LF/HF index and galvanic skin response were recorded before and during exposure to the noise. The level of noise annoyance was determined at the end of each test session using the noise annoyance questionnaire according to ISO 15666.
Results: Repeated measures analysis of variance (RMANOVA) indicated that the difference between the values of neurophysiological indices and noise annoyance in different noise exposure scenarios was significant (P<0.05). The effect of different tonal sound levels on galvanic skin response and noise annoyance was significant (P<0.05). In addition, the effect of 65 dB tonal sound level and 55 dB speech sound level on the LF/HF index was reported to be significant (P<0.05). Also, the effect size of 1.919 in exposure to 65 dB tonal sound level had the highest value compared to other noise exposure scenarios for the noise annoyance variable.
Conclusion: Exposure to different levels of tonal noise and irrelevant speech leads to disruption of individuals' neurophysiological parameters and noise annoyance in individuals regarding some of their characteristics and personality traits.
