Maximum Noise Level Research Articles

Assessment of Ambient Noise Exposure among Medical Staff in Dental Clinics Center of Dammam Medical Complex, Saudi Arabia

Introduction: Exposure to loud noise is a major problem for medical staff, especially in dental clinics and laboratories. Aim: This research aims to assess the ambient noise in dental clinics and the impact of noise on medical staff in dental clinics at Dammam Medical Complex, Saudi Arabia. Materials and Methods: A Cross sectional study was performed. Ambient noise was measured using the sound level meter in various laboratories and clinics. Results: The data showed that the maximum noise levels were between 116 and 56 dB(A) with peak levels ranging from 116 to 106 dB(A) in the laboratory and clinic environment. There is a significant correlation with the number of medical personnel, the area of the laboratory or clinic and the number and nature of the equipment used with the sources and ambient noise in their workplace and with daily exposure might cause severe impact on hearing loss in such clinics. Conclusion: The study strongly recommends the implementation of preventive measures and should be for periodic medical examinations and educational programs of the highest priority for medical staff in clinics and dental laboratories.

Urbanization levels are associated with the start of the dawn chorus in vermilion flycatchers in Colombia

Increased urbanization leads to the modification of animal behavior, including the start of the dawn chorus in birds. The beginning of the dawn chorus has been studied in relation to the level of urban noise and nocturnal artificial light in oscine birds, with few studies in suboscines. We evaluated a possible relationship between the start of the dawn chorus and different urbanization levels in a suboscine, the vermilion flycatcher (Pyrocephalus rubinus), in seven locations in the city of Armenia (Colombia). We categorized the urbanization level in each location according to its percentage of built structures, into low and high levels. Observations were made during pre-dawn, starting at 00:00 hr. During each visit we recorded maximum noise levels, artificial light at night (ALAN) and time of first song. Males inhabiting the high urbanization locations started the dawn chorus on average 101 min before sunrise, while males in low urbanization levels did so on average 38 min before. Neither noise level nor ALAN explained this difference. We discuss that, for suboscines, another urban-related factor (ambient temperature) may be a key factor driving the onset of dawn chorus.

An automated setup to measure the linear and nonlinear magnetic ac-susceptibility down to 4 K with higher accuracy.

An automated stepper motor controlled ac-susceptibility setup has been developed to measure the phase resolved linear and nonlinear magnetic ac-susceptibilities of a material in the temperature range of 4 K-300 K with a frequency range of 0.1 Hz-1.5 kHz. A maximum dc-field of ±150 Oe can be superimposed with a maximum ac-field of 100 Oe in the same coil by using a homemade ac-dc superimposing circuit. The induced voltage in the detection coil is measured by a lock-in amplifier, and temperature is controlled by a temperature controller. The very common offset voltage drifting problem is resolved by implementing a two-point measurement technique at every temperature, field, and frequency using a stepper motor. Operation of the stepper motor is controlled by a homemade computer programmable driver circuit. Sensitivity of the setup is obtained around ∼10-7 emu, and relative accuracy of the measurement is much better than 0.1%. Higher harmonics can be measured with a maximum noise level of ±15 nV throughout the temperature, field, and frequency range.

Analysis and hygienic evaluation of noise burden in public education organizations in Saransk

Background . Noise pollution is a burden exerting a harmful and irritating effect on human health. Children are particularly sensitive to noise burden. In this connection, it is especially important to control the noise pollution level in public education organizations where children spend significant time. Objective . The study is aimed at determining objective and subjective parameters of noise pollution in public education organizations based on the analysis of data obtained by measuring noise levels in school campuses in Saransk and directly in classrooms, as well as by questioning the teachers of these schools. Methods . The measurement of noise burden was carried out in 10 schools using the noise and vibration level meter “Assistant” with class I accuracy. Noise measurements in school campuses and classrooms were performed in accordance with the GOST 23337-2014 requirements. Assessment of results was conducted in accordance with sanitary standards 2.2.4/2.1.8.562-96 “Noise in the workplace, residential and public buildings and housing developments”. Results . Based on noise measurement results, the highest noise levels were found in school № 2 (65.5 dBА on the campus, 51.2 dBA in the classroom) which is located in the center of a traffic interchange. The lowest noise parameters were found in school № 35 (45.2 dBА on the campus, 37.7 dBА in the classroom) which is located in the residential quarter quite far away (242-321 m) from the main source of noise, the motorway. Conclusion . Study results attest that maximum noise levels at school campuses do not exceed the permissible exposure limit of 70 dBA. In all schools noise values conform to the noise standards (maximum sound pressure level in classrooms did not exceed 55 dBA).

Airport capacity evaluation based on air traffic activities big data

In order to evaluate the airport's comprehensive service capabilities, this paper considers the impact of air quality and noise on the airport environment under the big data of air traffic activities. In this study, the concept of environmental traffic capacity and big data are applied to the air traffic field. Recently, the airport air and noise pollution has been widely investigated and has become one of the major concerns of the potentially exposed people. This study explores the usage of governmental ambient air quality and noise standards to evaluate the airport operation capacities in the context of the era of big data. The first step is to analyze the typical airport operation scenario as the evaluation scenario. The second step is to use the air and noise emission assessment model for calculating the airport maximum air pollutant concentration and noise level. The final step is to establish a complete airport environment traffic capacity (AETC) evaluation process. As a case study, the capacity evaluation of Nanjing Lukou international airport (NKG) is performed using the above steps. In this case, significant associations between the pollutant concentrations/noise level and the air traffic volume were observed. The AETC of NKG was calculated with the established evaluation process successfully. The results show that the NKG maximum hourly air traffic volume is 120, daily air traffic volume is 770, and annual air traffic volume is 365,805, meeting the China Ambient Air Quality and Noise Standards. Although different air pollutants were investigated in this research, only the NOx was found to be the species that approaching the China governmental standards in this case. Thus, the airport NOx concentration was selected as the AETC limitation factor.

Evaluation Method for Façade Acoustic Insulation for a Corner Room: Discussion on the Results Obtained as a Function of the Source Position

The appropriate acoustic insulation project of building façades is of importance for the design of highly comfortable living environments. In some countries, national regulations require maximum noise levels inside rooms, or minimum sound insulation limits, to be respected. The acoustic insulation design of a façade is usually performed according to the ISO 12354-3 standard, which presents a calculation method based on the geometry of the room, the shape of the façade, the areas and the acoustic performances of the individual elements. The prescribed limits must be experimentally verified according to methods derived from international standards. However, the current versions of such standards do not provide details on how to perform the measurements and the calculation of the sound insulation for corner rooms. An important remark is that, depending on the position of the sound source used for the measurements, different results of the standardized sound insulation are obtained. This article proposes a new method for calculating the façade insulation of corner rooms by introducing the acoustic attenuation due to the diffraction of the corner and the distance of the sound source from the façades, estimated through simulations and experimentally validated.

Comparison of wind turbine-only noise levels measured at operating wind farms in the United States to noise levels predicted using ISO 9613-2:1996

This paper describes robust and effective methods for the measurement of noise emissions from utility-scale wind farms and the analysis of the resulting data for determining compliance with noise level limits and standards. The methods call for primarily unattended monitoring of noise levels, wind speeds, and turbine operating conditions over many weeks, in some cases months, in order to capture the recurring maximum wind turbine-only noise level at a receptor (i.e., residence). This condition occurs when the nearest turbines are producing full acoustic output while noise from background sources is very low (particularly that from wind). Presented are the results of noise compliance measurement studies applying these methods conducted by Hankard Environmental, encompassing eight projects and 35 measurement locations in the Northeast, Midwest, and Plains regions of the United States (U.S.) The results of these measurements are used to assess the accuracy of the ISO 9613-2:1996 method in predicting wind turbine noise levels at residences. These results can be used by wind energy developers to accurately design projects to meet applicable limits and standards and give all parties involved in the permitting process a greater degree of confidence in predictions and greater clarity during compliance measurements.

Noise Level and its Sources in Neonatal Intensive Care Units of Selected Public Hospitals in Kigali City

Background
 Noise in the neonatal intensive care unit (NICU) has an impact on the developmental progress of neonates, especially preterm. Technology advancement has improved the life of preterm neonates, but also changed NICU into a noisy place.
 Objective
 To measure the noise levels and identify its sources in NICU at selected public hospitals in Kigali city`
 Methods
 A quantitative cross-sectional descriptive study. A sound level meter was used in recording the Sound level in six different locations of the NICUs at five different times. An observational checklist was used to identify possible sources of noise. Data were analysed using descriptive and inferential statistics (ANOVA).
 Results
 Sound levels recorded in all the NICUs were high ranging from 61.8 decibel (dB) to 77.0 dB, greater than the 45 dB recommended by the American Association of Pediatrics (AAP). The maximum noise level was 77.0 dB. Ward rounds had the highest noise levels, and lunchtime had the lowest noise levels in all hospitals. Noise levels were high at the station near the entrance in all NICU rooms.
 Conclusion
 In all NICUs, the noise level generated was greater than the standard limits established by AAP. Neonates need noise-free environment as excess noise has an impact on their wellbeing.
 Rwanda J Med Health Sci 2020;3(2):115-127

Effect of ternary blends on the noise, vibration, and emission characteristics of an automotive spark ignition engine

ABSTRACT The type of fuel, engine speed, and load are some of the parameters, which influence engine noise, vibrations, and exhaust emissions of an internal combustion engine. The present investigation is carried out to study the effect of isobutanol addition to methanol-gasoline blends on engine’s noise, vibration, and emission characteristics of an unmodified automotive SI engine operated at various engine speeds. The engine was fueled with 10 and 15% (v/v) blended fuels of methanol-gasoline (M10, M15) and methanol-isobutanol-gasoline (iBM10, iBM15). The blended fuels produced relatively high noise levels and less vibration in the vertical and longitudinal direction when compared with gasoline operation. The maximum noise level of 64.43dBA observed with the M15 blend and which is 4 dBA higher than gasoline. Only a slight variation in the total fuel consumption observed for all the test fuels at higher engine speeds. The emissions from the test fuels iBM10 and iBM15 showed a reduction in HC by 25 and 10% and CO emissions by 65 and 87%, respectively. The methanol-gasoline blends produced slightly higher CO2 and NOx emissions than gasoline.

ПРЕДЛОЖЕНИЯ ПО КОРРЕКТИРОВКЕ МЕТОДИК, РЕГЛАМЕНТИРУЮЩИХ ПРОВЕДЕНИЕ ШУМОМЕТРИЧЕСКИХ И ВИБРОМЕТРИЧЕСКИХ ИСПЫТАНИЙ ПАССАЖИРСКИХ ВАГОНОВ

The work purpose is the development of suggestions on the improvement of labor conditions for passenger car conductors. In the paper there is shown information on conductor health, diseases connected with the vibration high level impact. On the basis of the experience of CC SA “TIV” for the solution of the problem specified there are introduced suggestions on changes of the standard base regulating the fulfillment of noise metering and vibration metering test. 
 The expediency of the changes offered is also substantiated with the potential of modern instrument-ware. The absence of the necessity for the definition of vibration indices at a motion speed up to 80 km/h is shown. A possibility to obtain objective data on vibration processes in a car during measures with the 20 km/h intervals is called into question. A regularity connecting the frequencies of dominating vibration with the speed of a car motion is determined. There are given specific recommendations on the adjustment of procedures to obtain reliable information on noise and vibration perceived by passengers and service personnel. It is emphasized that maximum noise levels arise at maximum vibration levels therefore there is drawn a conclusion on the expediency of the synchronization of these tests. On the basis of the material presented in the work the following conclusions are drawn: in the resent years are not observed improvements in conductor morbidity rates connected with the impact of vibration higher levels; on the consequences of vibration impact upon passengers it is possible to judge by a health state of conductors; the introduction of the changes offered will result also in time saving and cost decrease of test fulfillment.

Evaluation of Noise Emission in a Textile Plant

Textile industry is characterized by the use of complicated machinery in mass production methods in order to meet increased consumption demands. This situation brings with it some issues for the employees. Many of the machines used in textile industry are operating at high noise levels. In this study, noise measurements taken from dyeing/finishing and weaving divisions in an integrated textile factory in Malatya city, Turkey were evaluated. Frequency distribution of dominant noise is also examined. Workers in weaving division were exposed to higher levels of noise than those in dyeing/finishing. Accordingly, the noise level in weaving ranged from 99.2 to 101.1 dBA, while that in dyeing/finishing ranged from 77.1 to 79.3 dBA. It is also outside the 4000 Hz frequency zone, where the dominant frequencies of the maximum noise levels exposed by those working in the measured divisions fall in the middle frequency range to which the ear is most sensitive. Considering the frequency distribution, noise levels in the 4000 Hz region are calculated to be between 84.2 and 86.8 dBA in the weaving division and 60.0 to 61.9 dBA in the dyeing/finishing division. A noise histogram showed that noise in the weaving division had spread over a wider range than the dyeing/finishing division.

An experimental investigation on combustion, performance and ringing operation characteristics of a low compression ratio early direct injection HCCI engine with ethanol fuel blends

Homogenous charged compression ignition engines can be an alternative to spark ignition and compression ignition engines due to their high thermal efficiency and low exhaust emission characteristics. In this study, the effects of ethanol fuel blends on combustion, performance and ringing operation characteristics were investigated in an early direct injection homogenous charged compression ignition engine at a low compression ratio of 9.2. During the experiments, n-heptane, E10, E15 and E20 were used as test fuels. The experiments were carried out at three different intake air temperatures which are 353, 373 and 393 K, 800–1800 rpm engine speed range and 0.3–0.75 equivalence ratio range. The variations of indicated mean effective pressure, in-cylinder pressure, heat release rate, CA10, CA50, CA90, combustion duration, combustion efficiency, thermal efficiency, indicated specific fuel consumption, maximum pressure rise rate, coefficient of variation of indicated mean effective pressure, ringing intensity and combustion noise level were evaluated. The results showed that the maximum in-cylinder pressure and heat release rate decreased with the increase of ethanol fuel ratio in the mixture. The CA10, CA50 and CA90 advanced and the combustion duration shortened with the increase of the n-heptane fuel in the mixture. The coefficient of variation of indicated mean effective pressure increased with the increase of the ethanol fuel ratio in the mixture at misfiring region. The maximum pressure rise rate, ringing intensity and combustion noise level were tended to increase with the increase of the equivalence ratio at all test conditions.

Acoustic Energy Harvesting in Nigeria: Prospects, Technical Problems and Socio-Economic Obstacles

Aims: To investigate the prospects or potentials of acoustic energy harvesting in Nigeria as well as highlight technical problems and socio-economic obstacles.
 Study Design: The study re-examined existing data, noise levels and noise power, from road traffic, aircraft, industrial/occupational, outdoor and indoor noise sources. Noise levels and noise power obtained from recent measurements of such noise sources were also examined and analyzed. The data were compared with values from noise sources used for electricity in other countries of the world. Technical problems and socio-economic obstacles have been highlighted.
 Place and Duration of Study: The study was carried out in Abakaliki, Ebonyi State, Nigeria. The duration was one year: April, 2019 and April, 2020.
 Methodology: Wide range noise level measurements, analysis and re-examination of existing data on road traffic, aircraft, industrial/occupational, outdoor and indoor noise were conducted, in line with the objectives of the study, in cities, industries as well as homes with different noise features. Measurements were carried out using sound level meter, SLM, (Bruel and Kjaer 2203) with – octave band filter and SLM, EXTECH 407750 with RS232, sound level recorder (B & K 7005), and noise level (statistical) analyzer (B & K 2121) to obtain noise levels and indices. Also, noise power was subsequently obtained for each of the various noise levels and indices.
 Results: Maximum noise levels, Lmax.; noise power, Wmax.; octave band pressure levels, BPLs; and other indices for the different noise sources were determined. Lmax. and Wmax for aircraft were as high as 116 dB and 0.4 W, respectively, while those for industry and road traffic ranged from 104.0 dB-131.0 dB and 67.5 dB-85.6 dB corresponding to 0.025 W-12.59 W and 0.0000056 W-0.00036 W, respectively. Spectral power of road traffic noise varied between 5.17 x 10-5 W and 9.69 x 10-3 W. Outdoor and household noise sources had Lmax. of up to 48.5 dB and 88.0 dB, that is, 0.000000071 W and 0.00063 W, for quiet and noisy periods, respectively. It was observed that road traffic noise has the highest potential for acoustic energy harvesting in Nigeria being reasonably steady over time, especially, on intra-city roads. Availability of tricycles/motorcycles in abundance and frequent use of horn by motorists support this assertion. The noise levels and noise power from these sources obtained in this investigation are higher than those that have been used as input to acoustic energy harvesters (AEHs) such as piezoelectric based and triboelectric nanogenerators (TRENGs) to achieve known efficiencies as reported elsewhere.
 Conclusion: The noise power is such that it could be used in powering microelectronic components, devices and in lighting light emitting diodes (LEDs). Power supply (PS) audio noise harvesters (ANHs) have been identified as potential noise energy sources since there is wide range use of air-conditioned by the political class, elites and government agencies in Nigeria where maximum temperature of 47.2°C is attainable. These findings show the viability of AEH in Nigeria and their addition to the existing body of knowledge in the emerging area of AEH will open a new window of research in AEH in this part of the world. Other prospects of AEH in Nigeria, technical problems and socio-economic obstacles are highlighted.

Noise Reduction Based on Training Intervention and Using Visual Signs in Neonatal Intensive Care Units (NICUs)

Noise may cause hearing damage and delayed growth and development in newborns in neonatal intensive care units. Hence, it is necessary to reduce noise in these environments. Training and use of visual signs have been investigated as the interventional strategies with the aim of reducing noise level and exposure in neonatal intensive care units. This quasi-experimental study (before and after design) was conducted in the NICU of Birjand University of Medical Sciences Hospital (BUMSH NICU). According to ISO9612 standard, equivalent and maximum noise level in the NICU was measured by a calibrated sound level meter TES model 1358C at various stations during different shifts. Subsequently, the training and visual signs (flags and posters) were utilized as the interventions and SPSS version 18 was used for data analysis. The average equivalent and maximum noise level were calculated between 43.5–69.2 and 55.3–79.2 dBA, respectively, which is above the standards recommended by the American Academy of Pediatrics (AAP). Staff conversation, equipment and alarms were among the main sources of noise pollution. The equivalent noise level showed meaningful reduction before and after the interventions (personnel training and visual signs usage) at night. Noise in our NICU was greater than the recommended sound levels of 45 dBA. However, training and visual signs interventions seemed effective in reducing noise levels, particularly during the night shift. Since conversation was identified as the main noise source, future research is recommended to determine personality traits in healthcare professionals and promote a culture of silence.

Noise patterns in visceral surgical procedures: Analysis of second-by-second dBA data of 599 procedures over the course of one year

The objective of this study is to analyze noise patterns during 599 visceral surgical procedures. Considering work-safety regulations, we will identify immanent noise patterns during major visceral surgeries. Increased levels of noise are known to have negative health impacts. Based on a very fine-grained data collection over a year, this study will introduce a new procedure for visual representation of intra-surgery noise progression and pave new paths for future research on noise reduction in visceral surgery. Digital decibel sound-level meters were used to record the total noise in three operating theatres in one-second cycles over a year. These data were matched to archival data on surgery characteristics. Because surgeries inherently vary in length, we developed a new procedure to normalize surgery times to run cross-surgery comparisons. Based on this procedure, dBA values were adjusted to each normalized time point. Noise-level patterns are presented for surgeries contingent on important surgery characteristics: 16 different surgery types, operation method, day/night time point and operation complexity (complexity levels 1–3). This serves to cover a wide spectrum of day-to-day surgeries. The noise patterns reveal significant sound level differences of about 1 dBA, with the most-common noise level being spread between 55 and 60 dBA. This indicates a sound situation in many of the surgeries studied likely to cause stress in patients and staff. Absolute and relative risks of meeting or exceeding 60 dBA differ considerably across operation types. In conclusion, the study reveals that maximum noise levels of 55 dBA are frequently exceeded during visceral surgical procedures. Especially complex surgeries show, on average, a higher noise exposure. Our findings warrant active noise management for visceral surgery to reduce potential negative impacts of noise on surgical performance and outcome.

On the feasibility of measuring physiologic and self-reported sleep disturbance by aircraft noise on a national scale: A pilot study around Atlanta airport

Aircraft noise can disturb sleep and impair recuperation. Research is needed to develop exposure-response relationships that are representative of noise-exposed communities and can be used to inform noise mitigation policy in the United States. For a national field study on physiologic response to aircraft noise during sleep to be feasible, an inexpensive yet sound study methodology is needed. In the pilot study presented here, the methodology of using electrocardiography and actigraphy to monitor sleep was implemented around Atlanta Hartsfield-Jackson International Airport (ATL). The primary objective was to evaluate the quality and quantity of data that could be obtained with the following study approaches: recruiting participants by postal questionnaire, shipping them the physiologic and noise measurement equipment, and the unattended setup of the equipment and recording of data by the participants themselves. The secondary objective was to compare objective and subjective measures of sleep and health between groups exposed to different levels of nocturnal aircraft noise. We mailed 4080 questionnaires containing items on sleep, health and noise disturbance to residences around ATL that were exposed to at least 35 dB Lnight aircraft noise. From 407 questionnaire respondents, 34 participants completed five nights of unattended sleep measurements. Data of sufficient quality and quantity to investigate the effects of aircraft noise on sleep were obtained. Self-reported awakenings increased as a function of the highest maximum aircraft noise level occurring during the sleep period. Event-related physiologic awakenings increased as a function of the maximum noise level of individual aircraft noise events, although this effect was of only borderline statistical significance (p = 0.057) likely due to the low sample size of this pilot study. The approach used in the presented pilot study has been demonstrated to be feasible for the purpose of the larger-scale study among a representative population around multiple airports in the future.

Aircraft Noise of Airport Community in Korea

Aircraft noise is one of the serious environmental noises with the increased use of flight traffic. The purpose of this study is to understand aircraft noise levels of airport communities in Korea using baseline data for audiologic management. Aircraft noise levels were retrieved from the National Noise Information System every month between 2004 and 2018. We reviewed aircraft noise levels obtained from total of 111 airport communities across 14 airports. In order to understand aircraft noise levels of civil and military airports, the aircraft noise levels measured in civil and military airport communities compared with the noise levels from civil airport communities. The data showed average 71-73 weight equivalent continuous perceived noise level (WECPNL) for fifteen years across airport cities and the average noise levels did not increase over time between 2004 and 2018 years. The civil and military airports showed about 12 WECPNLs of increased noise levels compared to the civil airports. The most civil and military airport communities, including Gwangju, Gunsan, Daegu, Wonju, and Cheongju generated the maximum noise levels and ranked as the highest airport for aircraft noise levels. Although aircraft noise levels in airport communities were similar over the past decade, civil and military airports generated increased noised levels compared to civil airports due to jet plane noises and other military-related noises. Careful consideration is necessary to implement noise reduction policy for civil and military airport communities. Ongoing noise control, hearing monitoring, education, and relevant policies are required to improve the quality of life in the airport community residences.

DETERMINATION OF ACTUAL DISTANCES FOR INSTALLATION OF A 100 kVA NON-SOUND PROOF POWER GENERATOR AT RESIDENTIAL AREAS

Power generators should be professionally sited from the residential areas as noise from them demeans the superiority of our living. This work therefore presents determination of actual distances for installation of a 100 kVA non-sound proof power generator at residential areas. Measurements of noise levels with respect to distance, x from the generator were taken and linear regression method was used to analyse the data obtained. Environmental noise models were developed by using the relevant displayed parameters such as the maximum noise level of the generator, the attenuation coefficient and the coefficient of determination. The results obtained from the models developed, L(modelled) were compared with the results obtained from the physical measurements, L(measured) and there was insignificant difference between them. The results reveal that the distances, xc in metres in which its adverse effects covered in the residential areas were , while the distances, xs in metres at which it can be sited from the residential areas were . With the existence of x, the models developed in this work are recommended to be used as more reliable tools for environmental noise impact assessments.

Anthropogenic noise is associated with telomere length and carotenoid-based coloration in free-living nestling songbirds

Growing evidence suggests that anthropogenic noise has deleterious effects on the behavior and physiology of free-living animals. These effects may be particularly pronounced early in life, when developmental trajectories are sensitive to stressors, yet studies investigating developmental effects of noise exposure in free-living populations remain scarce. To elucidate the effects of noise exposure during development, we examined whether noise exposure is associated with shorter telomeres, duller carotenoid-based coloration and reduced body mass in nestlings of a common urban bird, the great tit (Parus major). We also assessed how the noise environment is related to reproductive success. We obtained long-term measurements of the noise environment, over a ∼24-h period, and characterized both the amplitude (measured by LAeq, LA90, LA10, LAmax) and variance in noise levels, since more stochastic, as well as louder, noise regimes might be more likely to induce stress. In our urban population, noise levels varied substantially, with louder, but less variable, noise characteristic of areas adjacent to a highway. Noise levels were also highly repeatable, suggesting that individuals experience consistent differences in noise exposure. The amplitude of noise near nest boxes was associated with shorter telomeres among smaller, but not larger, brood members. In addition, carotenoid chroma and hue were positively associated with variance in average and maximum noise levels, and average reflectance was negatively associated with variance in background noise. Independent of noise, hue was positively related to telomere length. Nestling mass and reproductive success were unaffected by noise exposure. Results indicate that multiple dimensions of the noise environment, or factors associated with the noise environment, could affect the phenotype of developing organisms, that noise exposure, or correlated variables, might have the strongest effects on sensitive groups of individuals, and that carotenoid hue could serve as a signal of early-life telomere length.

Traffic Noise Assessment among Residential Environment in Batu Pahat, Johore, Malaysia

Noise pollution arises as a severe problem to the community and ground transportation has highly impacted noise environment of the neighbourhood. In the present study, six stations were selected from three different locations in order to assess the traffic noise impact among residential area along Jalan Kluang, Batu Pahat. The objectives of this study focused on two main stages: (1) determination of noise indices; and (2) assessment of traffic noise impact. The noise indices such as equivalent continuous noise level (LAeq), noise level exceeded 10% (L10), 90% (L90) and the maximum noise level (LAFmax) of peak hours measurement time were determined using sound level meter (SLM) at all six stations. Besides, traffic noise index (TNI) and noise pollution level (LNP) were calculated based on the measured noise indices to expose the traffic noise impact. Overall, the result of the present study showed that residential area faces traffic noise disturbance partially whereby 50% of the stations exceeded the DOE standard which was 55dBA. Nevertheless, the residents living nearby Jalan Kluang are commonly facing traffic noise nuisance, but stations located further inside residential areas tend to have more residential background noises apart from traffic influence.