Noise pollution in rail transport. Case study: Baghdad subway

Environmental noise is a significant public health issue, particularly in rapidly urbanizing cities where commercial activities contribute to elevated noise pollution. Despite its numerous implications, few studies have focused on noise levels in commercial environments in developing countries. This study aims to fill this existing gap by assessing background noise levels in four commercial areas of Freetown, Sierra Leone: Aberdeen Market, Godrich Street, Jui Junction, and Sani Abacha Street. Using a calibrated handheld sound level meter, measurements were taken during daytime, evening, and nighttime periods over one week. Noise levels were analyzed using the day-evening-night equivalent continuous noise level (Lden) and statistical methods to assess compliance with World Health Organization (WHO) guidelines. Results revealed that all areas exhibit average noise levels above the WHO recommended limit of 70 dBA during daytime and evening hours, with Godrich Street and Aberdeen Market exhibiting the highest average daytime noise level (95.35 dBA) and the lowest average nighttime noise level (53.05 dBA) respectively. Godrich Street recorded the highest Lden value and shortest allowed exposure of 93.34 dBA and 1.17 hours respectively, indicating the most significant risk of prolonged exposure. Recommendations include creating designated quiet zones tailored to local commercial layouts, stricter enforcement of noise regulations, public awareness campaigns on hearing protection, and regular noise monitoring to guide urban planning. This study provides crucial insights for mitigating noise pollution and improving urban sustainability in developing nations.

Traffic noise has been recognized as a serious threat to the quality of life in most industrialised nations. Klang valley is rapidly emerging as industrialized and urbanized city and has started facing severe noise pollution problems. Urban noise quality assessment is studied in three residential areas; Desa Tun Razak, Kinrara Court and Taman Sentul Utama. Noise pollution indices of L10, L50, L90, Lmax and Lmin as well as equivalent continuous noise level (Leq) were measured for all dwellings. Noise indices results illustrate that Desa Tun Razak recorded the highest values of noise levels among three studied sites. Results also indicate that the highest Leq of 75.7 dB(A) was observed in Desa Tun Razak followed by 74.3 dB(A) in Kinrara Court, and 72.1 dB(A) in Taman Sentul Utama. The noise assessment study clearly reveals the alarming condition of noise pollution in residential areas of Klang Valley as the noise level measured exceeded permissible limit by WHO and Malaysia Guidelines.

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.

The Noise Levels database has been developed at the Canadian Centre for Occupational Health and Safety for the computerized information system, CCINFO. The database documents measured noise levels from a broad spectrum of industrial settings. Industrial hygienists, noise control engineers, researchers, health and safety committee members, and appropriate government agency personnel are the main intended audience. Noise Levels is a textual‐numeric ‘source’ database of direct measurements, although bibliographic citations are also provided. The data for Noise Levels is gathered from both published and unpublished sources. Each record provides explicit information on the noise source (for example, piece of equipment), the industry, operation associated with the noise production, and the occupational categories. Additional information is provided on the type of noise, exposure duration per day, the presence of engineering controls, and the use of ear protection. Measurement data consists of one or more of the following: Sound Pressure Level (SPL) in dB(A), Time Weighted Average (TWA), Equivalent Continuous Noise Level (ECNL), and the octave band analysis. The primary goals of the database are to encourage sharing of industrial noise data and to promote standardized reporting of noise measurements.

This study investigates the acoustic conditions of a design studio (Studio 130) in the Department of Interior Architecture and Environmental Design at Afyon Kocatepe University by integrating 14 weeks of continuous noise measurements with perception data collected from 192 students. Noise measurements were conducted in accordance with ISO 3382-3:2022 guidelines at three locations—window front, door side, and studio midpoint—during morning, noon, and evening periods, with 10 min recordings at each session. The results indicate that when students were present, the equivalent continuous noise level (Leq) reached an average of 65.5 dB(A), with peak levels rising to 72.3 dB(A) during jury sessions. These values substantially exceed the recommended 35 dB(A) classroom threshold by the World Health Organization and the 35–45 dB(A) limits specified in national regulations for indoor educational spaces. Survey findings reveal that 88% of students experienced loss of concentration, 72% reported decreased productivity, 60% had difficulty communicating, and 52% reported fatigue due to noise exposure. Pearson correlation analysis demonstrated a strong relationship between measured noise levels and reported negative effects (r = 0.966). Moreover, independent samples t-test results confirmed that student presence significantly increased studio noise levels (t = 4.98, p < 0.001). The novelty of this research lies in its combined use of longitudinal objective measurements and subjective perception data, addressing the unique open-plan, collaborative, and critique-based pedagogical structure of design studios. The findings highlight that acoustic comfort is a critical component of learning quality in studio-based education. Based on the results, the study proposes several design and material interventions—including spatial dividers, acoustic ceiling panels, fabric-wrapped absorbers, and impact-reducing flooring—to enhance auditory comfort. Overall, the study emphasizes the necessity of integrating acoustic design strategies into studio pedagogy to support concentration, communication, and learning performance.

Present work was carried out to collect primary data from the field with the help of noise meter and thus spatial anddiurnal variation of background and aircraft noise level was analyzed. Seventeen sampling sites were chosennearby Tribhuwan International Airport (TIA) and air route of aircraft flyover. Noise measurements were carried outunder normal atmospheric environmental condition at temperature ranges from 25°C-30°C excluding rainy andwindy days. Among the sampling sites, the Equivalent Continuous Noise Level (LAeq) of background noise measuredmaximum at Balkumari (73.2 dBA) and minimum at Datidol (49.2 dBA). Noise meter was allowed to record aircraftnoise level when aircraft produced noise greater than background noise level and recorded until it reduced tobackground noise level. The maximum value of aircraft noise level, (LAeq) measured at Gothatar (101.5 dBA) whichlies north east from the TIA and at the same height as the airport ground and minimum at Datidol (63.5 dBA).Toanalyse the spatial variation of aircraft noise of different sampling sites, contour map was plotted with the help oforigin software. The LAeq of more than 60 percent sampling sites fall under the severe noise exposure class (> 75dBA) which causes substantial hearing loss. Implementation of noise control measurement and public awarenessare recommended to control adverse effect of noise pollution.DOI: http://dx.doi.org/10.3126/njst.v15i1.12031Nepal Journal of Science and TechnologyVol. 15, No.1 (2014) 139-144

Living in cities, people are faced with various problems that arise in everyday life. One of the most harmful problems that causes diseases in humans is noise pollution. The growing noise pollution of the big city also causes a lot of troubles to the citizens, negatively affects their health and mental condition. With the development of all types of transport, intensive construction, noise loads per person increase, causing its annoyance, mental imbalance, insomnia and, as a consequence, cardiovascular and mental illness. Now, in the streets of Kyiv in many regions, noise sometimes reaches 80-90 in the daytime, and 50-60 decibels at night, which is not a normal phenomenon. So, it was decided to find a site where noise would exceed the norm, and the main source of its nature would be the railroad.Having conducted experimental research on this section of the railway, noise levels were determined. Consequently, the equivalent noise level is 61 dBA, equivalent to the noise level of the flow of trains was 64 dBa, the maximum noise figure recorded in this section was 85 dBA. This experiment was conducted at night with the greatest intensity of trains. So, as the standard (DBN 360-92), the equivalent noise level in the period from 23 h - 7 h should not exceed 45 dBA, and the maximum noise level should not exceed 60 dBA. So we see a significant deviation from the norms, so you need to develop methods to combat noise. Since the selected site was densely built up, which made it impossible to combat noise by the method of forest plantations, so this issue was solved by establishing appropriate noise protection structures that would operate on different sources. Knowing that the noise arises not only from the rumble of the tractor of our tractor train, but also the rattle of the wheels on the track and the flow of air of the train body. So, to reduce noise, you need to consider all these sources.Consequently, in order to reduce the noise caused by rolling the wheel along the track, it was proposed to install road dampers and liners that reduce noise to 10 dB. And to reduce the noise already in the air, it is proposed to install noise protection screens of a height of at least 2m, which allows to reduce the noise level by another 15 dBA. Execution of these conditions will allow us to reduce the noise level in this area by 16 - 20 dBA. (the equivalent noise level should be reduced to 41-45 dBA).Consequently, this experimental study carried out showed us the need to carry out such experiments not only along the whole railway connection of the city of Kyiv or other cities of Ukraine, but also measurements on automobile or ship solutions or construction sites. This will detect problem areas, and depending on the source of noise, fight with them to improve the noise background. And this, in turn, will have a positive effect on the psychological state of man.So let's make a world in which we live better!

Diwali (or Deepavali) is one of the most glamorous cultural festivals in India. It is the festival of light and is celebrated every year during the month of November with great firework displays. Burning of different fireworks generates acute noise and toxic fumes, which lead to noise and air pollution in the environment. The excessive use of fireworks aggravates the level of air and noise pollution and causes adverse impacts on human health. The present paper assesses the noise pollution and air pollution during Diwali in Sambalpur City, one of the premier cities in the western part of Odisha State in Eastern India. The noise level is measured on Diwali day and is compared with that on normal days. Similarly, air quality is measured on Diwali day and compared with that on normal days (pre-Diwali and post-Diwali). The average equivalent continuous noise levels (L eq) and noise pollution levels have increased in all areas on Diwali compared with those on non-Diwali days. It is also observed that there is a significant rise of air pollutants, total suspended particulate matter, PM10, PM2.5, sulfur dioxide (SO2) and nitrogen dioxide (NO2) in ambient air due to burning of crackers in Diwali.

Equivalent Continuous Noise Level

This paper gives the results of the TRRL research programme into the noise from road construction operations. The paper deals with the measurement of noise from individual items of plant over long periods at the site boundary, with the prediction and monitoring of noise and with various methods of noise control. The noise of individual items of plant can be described in terms of a single parameter, the event energy noise level, and this parameter can be used as input to a noise prediction method. The equivalent energy continuous noise level (leq) at the site boundary can be calculated using the prediction method. The method is capable of predictions accurate to plus or minus 2db(a) when sufficient information is available as input data. Several methods of noise control are identified; efficient silencing of the plant is the most effective. In a case study on a semi-urban motorway scheme, it was found that a reduction in leq of up to 15 db(a) in noise-sensitive areas could be achieved, the associated costs being about 10% of the earthworks cost. The paper suggests a procedure for the assessment of road construction noise which employs some of the methods described. /TRRL/

Noise level in the surroundings of traffic routes mainly depends from traffic volume, flow composition, speed of the vehicles as well as from the cross-section and road longitudinal gradient. Under higher speeds significant influence on the noise level has also tyre/road noise. Tyre/road noise depends on type and pavement condition state, specifically from the surface macrotexture. The influence of macrotexture is varying and strictly connected with the type of vehicles, tyres characteristics, frequencies of emitted noise. On the base of investigations of the rolling noise applying Statistical Pass-By method along the Polish roads the paper presents elaborated dependences and fixed values of differences between maximum noise levels under passing multiple-axle heavy vehicle and passenger car on the asphalt concrete surface, stone mastic asphalt and the surface dressing. The functional dependences between maximum rolling noise levels in the range of complete level and in the octave band spectra: 250 Hz, 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz and between the surface macrotexture described by mean profile depth, and logarithm of vehicle speed and adequate nomograms were evaluated in the paper. On this base the values of differences in the levels of emitted noise from passing heavy vehicle and passenger car in function of speed and surface macrotexture were computed. The manuscript also presents how surface macrotexture and traffic flow composition have influence on equivalent noise level in the road vicinity under equal traffic volume.

Equivalent magnetic noise levels at 1 Hz of three GMI samples have been experimentally determined for different excitation conditions related to both dc current and ac excitation amplitude. These three wires or cylindrical-shaped samples are from the exact same alloy composition and obtained from the same fabrication process. The only difference is their diameter which are 80 im, 100 im and 120 im, since this parameter has been identified as an important factor involved in GMI low frequency noise level. Indeed, from the recently proposed model, briefly reminded here, the equivalent magnetic noise level should decrease with the square of the wire diameter. These low frequency equivalent magnetic noise level measurements have been conducted with coherence measurements showing that the main noise source responsible of this noise level is the intrinsic noise of the GMI sensor. Obtained results have then been compared to the expected noise level from the theoretical model, showing a relative good agreement, validating the behavior regarding wire diameter.

Forty representative roadway locations were randomly selected for monitoring traffic flow and noise levels. At local streets, equivalent noise level (Leq) ranged between 56 to 71; at collector streets traffic areas 70 to 83; at arterial roadway 75 to 86 and at freeway roadway areas 75 to 88 dBA during day and night time respectively. Consequently, the level of noise pollution from traffic even at the present time, exceed the outdoor standard limit by a significant margin. The present unplanned growth of residential and commercial infrastructures will adversely affect the level of traffic congestion and noise pollution in Metropolitan Kuwait. There is an urgent need for improving the urban public’s education concerning daily travel and its impact on both the economy and the environment of the state, as well as on the welfare and health of the urban residents. Maximum policy makers’ attentions should be given to promote the use of public transit and non-motorised modes of urban travel in Kuwait.

In order to investigate the physiological effects of airport noise exposure on organisms, in this study, we exposed Sprague-Dawley rats in soundproof chambers to previously recorded aircraft-related noise for 36 days. For comparison, we also used unexposed control rats. Noise was arranged according to aircraft flight schedules and was adjusted to its weighted equivalent continuous perceive noise level (LWECPN) of 75 dB and 80 dB for the two experimental groups. We examined rat behavior through open field experiments and measured the concentrations of serum neurotransmitters (norepinephrine (NE) and 5-hydroxytryptamine (5-HT)) by high performance liquid chromatography-fluorimetric detection (HPLC-FLD). Our results showed that rats that were exposed to airport noise of 80 dB spent more time in the central part of the open field, the number of cross-lattices they crossed reduced significantly (P<;0.05), and their frequency of grooming and defecation increased significantly (P<;0.05), compared to control animals. The concentrations of serum NE of experimental groups were higher than that of the control group, and a dose-effect relationship was seen between NE concentration and the intensity of noise exposure. On the contrary, serum 5-HT concentrations of the experimental groups were always lower than that of the control group.

&lt;div class="htmlview paragraph"&gt;As a foundation for the development of a new motor vehicle test approval procedure for noise emission measurements, the different parameters defining the noise levels from passenger cars in urban traffic is discussed. The primary parameters are engine speed, engine load and under certain conditions; the vehicle speed. These parameters are controlled by a number of secondary parameters, which can be categorised into 3 groups: vehicle related, traffic related and driver related parameters. Developing a new test method, the vehicle variables such as power/weight, power/engine displacement and gear system are the most important to consider.&lt;/div&gt; &lt;div class="htmlview paragraph"&gt;Equivalent noise level or sound power level are preferable noise descriptors for a type approval test. A better correlation to noise immission levels in urban traffic is then obtained.&lt;/div&gt;