Evaluating the noise exposure levels of different schools in noise-scapes of Kargil town: Ladakh,India

Abstract

Noise at school poses a serious challenge to the classroom atmosphere with negative impacts on teachers’ and students’ ability to listen and learn. Kargil town is the gateway to the Ladakh Himalayan region that remains cut from the rest of the world during the winter months. During the summer months, the region experiences a spike in traffic activity. The current study was designed to assess noise exposure levels in schools within the Kargil town administrative boundaries. The result indicates that indoor, as well as the outdoor Equivalent noise level (LA_eq), in the schools located in Commercial area (58.3 ± 7.7 & 60.0 ± 1.9 dBA) Highway area (57.4 ± 8.1 & 63.0 ± 2.3 dBA) and Residential area (52.9 ± 9.8 & 60.0 ± 1.9 dBA) was above the permissible limits of World Health Organization and Central Pollution Control Board (CPCB) India. The highest indoor and outdoor Noise Climate was (15.4 ± 3.9 & 19.8 ± 2.3 dBA) in the school located on the Highway area is due to the flow of heavy vehicular traffic on the Highway and the Traffic Noise Index was also high in schools located on the Highway (97.5 ± 7.6 dBA). The Noise Pollution Level (LNP) value was also found to be high in the Highway area (72.8 ± 10.7 & 82.8 ± 3.0 dBA). The findings of this study will be beneficial for policymakers and stakeholders in the context of noise pollution management in schools with evolving noisescape of Kargil town.

Keywords

Noise climate noise scape noise exposure noise pollution

Introduction

Noise as pollution is conceded worldwide as a severe problem that affects the quality of life.^1,2 Noise pollution is now globally assessed at different scales. For many years, valuations have been conducted for the appraisal of noise levels in many cities around different continents, including many cities in India like Caceres,³ Tehran,⁴ Michigan,⁵ Nigerian cities,⁶ Nagpur city,⁷ Nasik,⁸ Allahabad city,⁹ Guwahati,¹⁰ Mumbai, Delhi, and Chennai.¹¹ In parallel to big cities, noise pollution levels have exceeded the limits even in small cities and towns like Navsari city,¹² Burdwan town¹³ and Angul town.¹⁴ Environmental noise is becoming a ubiquitous encounter in human life. It is the exceptionable and deleterious sound created by different activities of humans that impacts the noise quality both outdoors and indoors.^15,16 Noise is termed as undesirable when it starts disturbing the normal activities of a person, such as working, sleeping, and having conversations.¹⁷ Noise pollution is often overlooked since it cannot be seen, smelled, or tasted yet has harmful effects on humans. That is why it is referred to as a silent killer.¹⁸

Noise is one of the major factors that affect the school’s environment.¹⁹ Despite the fact that most of the research on the actual learning environment in schools is unclear, research across a variety of fields and techniques indicates that noise has a detrimental effect on student learning.^20–22 Furthermore, noise can cause hindrance in the teaching and learning process, disrupt the achievement of many tasks, and increase the incidence of anti-social behaviour.^19,23 Environmental noise poses a severe threat to growing children because they do not have the physical, mental, and neurological maturity at this early age. Learning in classrooms can be easier through evenly distributed vocabulary and aural communication between teachers and students.^24–28 According to Sargent et al.²⁹(1980), outdoor noise impacts the student’s performance and behaviour, and students become tired sooner, particularly in a noisy environment where noise levels go beyond 75 dBA, such as a highway. Nittala et al.³⁰ (2014) and Ismail et al. (2015) revealed that traffic noise is the major contributing factor to noise in schools. Higher environmental noise >50 dBA in schools’ effects the student learning procedure.³⁰ Many problems related to health, such as annoyance, hypertension, blood-related problems etc. due to noise are the result of the ignorance of people towards the ill effects of noise.^31–37 Therefore, there is a need for suitable scientific data which strongly chains up noise exposure to a specific health problem.³⁸

Since noise is a growing problem, it is necessary to control and regulate it. There has been an immediate concern in developed countries to control the effect of noise, as evidenced by extensive anti-noise laws and regulations^39,40 (Table 1) as well as noise policies.^40,41 Although such measures remain on the backfoot in the developing countries, especially in India, due to the inclination of urbanization, industrialization, road network and the number of motor vehicles, these changes have likely led to an increase in noise levels that have negative effects on the citizens. Unfortunately, a huge number of the population do not consider noise pollution.^11,41,42 The government of India introduced a set of guidelines for regulation and control of noise known as the Noise Pollution (Regulation and Control) Rules 2000, framed under the Environment (Protection) Act, 1986. The ambient noise levels for different areas specified in the rules are indicated in (Table 2).

Table 1.

Recommended noise level standard and guidelines by WHO and selected countries.^39,40

Noise level limit	Noise level (L_eq)
Noise level limit	Day	Night
WHO	55	45
Germany (noise level guidelines)	45	35
Australia (recommended outdoor background noise level)	45	35
Japan (environmental quality standards)	45	35
Korea (environmental quality goal)	50	45
Philippines (environmental quality noise standards)	50	40
Iran (residential area)	55	45
Iran (commercial area)	65	55
Iran (industrial area)	75	65

Table 2.

National ambient noise standards.⁶³

Area code	Category of area	Limits in dB (A)
Area code	Category of area	Day time	Night time
(A)	Industrial area	75	70
(B)	Commercial area	65	55
(C)	Residential area	55	45
(D)	Silent zone	50	40

Source: Environment (protection) act, 1986 as amended in 2018.

Taking into consideration the health effect of noise pollution the Ministry of Environment, Forest and Climate change come up with the WHO guidelines for indoor noise which were set for the initial effects of noise exposures (Table 3).

Table 3.

WHO guidelines for standard limits of noise for schools.⁶³

Specific environment	Time base (hours)	Standard limits as per WHO guidelines
Specific environment	Time base (hours)	LAeq (dB)	Lmax fast (dB)
School class rooms and pre-schools, indoors	During class	35	—
Pre-school bedrooms, indoors	Sleeping time	30	45
School, playground outdoor	During play	55	—

Source: Central pollution control board, 11-September 2017.

Noise is recognised as an air pollutant under the Environmental Protection Act, 1986 by the Government of India. It is a serious and compelling environmental problem in various rapidly urbanising areas like cities and towns, which are the hubs of activities. Various research has already been conducted to evaluate the noise pollution load in many large and small cities in India, but a comprehensive national survey has not been conducted to assess the level of noise pollution in large and small growing towns in India as towns are the centre of activities after cities. Kargil is hosted as the gateway of Ladakh, and the NH-1D (National Highway-1D) passes through the centre of the town, which serves as the route of traffic, military convoys, and tourist flux. Kargil, the area’s second-fastest-growing town after Leh, is experiencing unacceptable noise conditions as a result of construction, traffic, and the growth of commercial buildings, which are causing a problem in the town. It also served as a hub of education and the district’s official zone, with over 20 primary and secondary schools and four higher secondary schools, so we find it important to monitor the noise level in various schools located throughout Kargil town. The objective of the study was to evaluate the status of indoor and outdoor noise levels in schools located in different noise scapes of the study area, viz., residential, commercial, and highway areas.

Methodology

Study area

Kargil is a mountainous, rugged, and high elevated area located at an altitude of 8000 feet in western Ladakh, north-western Jammu, and Kashmir along the banks of Suru River with a population of 1.43,000 (Census, 2011). The town lies in the Zanskar range of the Himalayas and along the line of control between India and Pakistan. Kargil town is located on National Highway 1D connecting Srinagar (southwest) and Leh (southeast), and is considered the gateway of Ladakh. The climate of the area is temperate and cold, with precipitation of less than 318 mm annually, mainly in the winter season in the form of snow. The Winter season starts at the beginning of December and ends in May, due to heavy snowfalls in the Zojila pass the district remains cut from the rest of the world for almost five to six months. During these six to seven months the traffic flow on NH-1D is at its peak due to Lorries carrying essential commodities and stocking food supplies for the inclement months of the year. The influx of tourists is also high during this period. Besides this, the military convoy also plies during these months, due to which the noise during this window period (summer months) increases resulting in increased noise exposure levels. In the present study noise monitoring was carried out in three Schools located in different noise scapes of Kargil town are presented in (Figure 1).

Figure 1.

Map of Kargil town showing distribution of study sites.

Materials and method

The noise monitoring was carried out in three Schools located in different areas of Kargil town from May 2018 to September 2018. The selection of school was based on the area viz. Sawab public school in residential area with >300 students, Govt, girl higher secondary school in Commercial area with >700 students, and Highschool poyen in Highway area with >300 students. The sampling of noise was recorded three times at each site during the weekdays. The sampling was done between (1000–1800 h). During each sampling of noise levels, 20 readings of SPL (Sound Pressure Level) were recorded in 10 min at an interval of 30 s for three working days in all the selected school using a Digital Sound Level Meter (Data logger model: 407,764A) Capable of measuring sound levels of 40–130 dBA. Noise observation was performed at a height of 1.5 m away from the chest. From these 20 readings of SPL several noise indices were calculated in Microsoft Office Excel 2018.

L_{e q} = 10 \log \sum_{i = 1}^{i = n} 10^{l i / 10} \times t_{i},

(1)

(1) Equivalent noise level LA_eq.⁴³

n = total number of sound samples.

l_i = noise level of any i^th sample.

t_i = time duration of ith sample expressed as fraction of total time sample.

(2) L₁₀: the noise level exceeding 10% of the time.

(3) L₉₀ = the noise level exceeding 90% of the time.

(4) Noise climate (NC): It is the extent over which the sound levels are fluctuating in a period of time and is calculated by the following equation.³⁰

N C = L_{10} - L_{90} .

(2)

(5) Traffic noise index (TNI)

T N I = L_{90} + 4 (L_{10} - L_{90}) - 30 (30 = c o r r e c t i o n f a c t o r)

(3)

(6) Noise pollution level (LNP) represents the variations in the sound signal. It is an indicator of pollution which includes both the quality and quantity of noise, hence it is a better indicator of sound pollution for physiological and psychological disturbance of the human environment. It is computed by the following relation.^44,45

L N P = L_{e q} + (L_{10} - L_{90}) .

(4)

The average noise level was measured and the data were stored and correlation was calculated in the Microsoft excel software.

Results

The present study has been made to appraise the noise status of schools located in different areas of Kargil town. The analysis of Indoor noise levels of schools in the different areas revealed that Govt. girl higher secondary school located in commercial areas exhibited a maximum Equivalent Noise Level (LA_eq) value of 58.3 ± 3.0 dBA, and Sawab public school located in the residential area exhibited minimum indoor L_eq value of 52.9 ± 9.8 dBA. The maximum indoor NC value of 15.4 ± 3.9 dBA was exhibited by high school Poyen located in the highway area. The minimum NC value of 13.3 ± 2.5 dBA was exhibited by govt. girl higher secondary school located in commercial area. The maximum LNP 72.8 ± 10.7 dBA was an exhibited by high school Poyen in highway area and the minimum LNP of 66.5 ± 12.6 dBA was exhibited by Sawab public school located in residential area (Table 4, Figure 2).

Table 4.

Indoor and outdoor noise levels of schools located in different noisescapes of Kargil town.

Sites	Indoor noise levels			Outdoor noise levels
Sites	LA_eq	NC	LNP	LA_eq	NC	LNP	TNI
Residential area	52.9 ± 9.8	13.6 ± 4.1	66.5 ± 12.6	60.0 ± 1.9	19.0 ± 4.3	80.4 ± 5.6	93.0 ± 14.8
Commercial area	58.3 ± 7.7	13.3 ± 2.5	71.6 ± 9.3	67.0 ± 2.1	12.6 ± 5.1	79.6 ± 4.4	78.3 ± 15.4
Highway area	57.4 ± 8.1	15.4 ± 3.9	72.8 ± 10.7	63.0 ± 2.3	19.8 ± 2.3	82.8 ± 3.0	97.5 ± 7.6

Figure 2.

Noise levels of Schools located in different noisescapes of Kargil town Ladakh.

The overall compilation of analytic data of outdoor noise levels of schools in different areas of Kargil town revealed that Govt. girl higher secondary school located in the commercial area exhibited maximum LA_eq values of 67.0 ± 2.1 dBA followed by high school Poyen located in highway area exhibited LA_eq value of 63.0 ± 2.3 dBA and the minimum L_eq value 60.0 ± 1.9 dBA was exhibited by Sawab public school located in residential Area. The maximum outdoor Noise Climate (NC) value of 19.8 ± 2.3 dBA was exhibited by high school Poyen located in highway area and the minimum NC value of 12.6 ± 5.1 dBA was exhibited by Govt. girl higher secondary school located in the commercial area. The maximum LNP value of 82 ± 3.0 dBA was exhibited by the school located in high school Poyen located in highway area and the minimum LNP value of 79.6 ± 4.4 dBA was exhibited by Govt. girl higher secondary school located in the commercial area. The Traffic Noise Index was high outside high school Poyen located in the highway area 97.5 ± 7.6 dBA and the minimum Traffic Noise Index was found outside the school located in the commercial area 78.3 ± 15.4 dBA. The statistical Pearson co-relation coefficient (r) between Outdoor and Indoor L_eq value revealed that School located in residential area (r = 0.64) exhibited significant (p ≤ .05) positive co-relation (Figure 3), Govt. girl higher secondary school (r = 0.49) in commercial area exhibited insignificant (p ≥ .05) positive co-relation (Figure 4) and high school Poyen along highway (r = 0.24) exhibited insignificant (p ≥ .05) positive co-relation (Figure 5). The details are given in (Table 5).

Figure 3.

Scatter plot showing indoor and outdoor L_eq value for school residential area.

Figure 4.

Scatter plot showing indoor and outdoor L_eq value for commercial area.

Figure 5.

Scatter plot showing indoor and outdoor L_eq value for highway area.

Table 5.

Pearson co-relation coefficient (r) between outdoor and indoor L_eq value.

Areas	Residential area	Commercial area	Highway area
Correlation-coefficient value	r = 0.80 (p ≤ .05)	r = 0.49 (p ≥ .05)	r = 0.24 (p ≥ .05)

Discussion

The result of the study revealed that the Equivalent Noise Level (LA_eq), which takes into account the total sound energy over the period, was higher than the provided standards of WHO (35–45 dB) and CPCB (50 dB) in and around all the schools located in different areas of Kargil town. The minimum indoor and outdoor L_eq values which were exhibited by Sawb public school located in the residential area (52.9 dBA and 60.0 dBA) were higher than the prescribed limits of the two organisations to prevent intrusion with speech,⁴⁶ as the quality of acoustics in a classroom is crucial for listening skills and, consequently, for the learning potential of the students.^47,48 The higher LA_eq levels in association with the threshold limits are a matter of concern. It should be noted that the students in all the schools may suffer from noise, which ultimately impacts their concentration, conception, and understanding in the classroom.^21,48 The result also showed that the schools with the higher number of students had approximately a higher L_eq value, i.e., the school located at the commercial area, the virtue of its location is also responsible for higher noise levels.^49–52 The observed L_eq of the schools were compared with other national and international studies and it was found that schools across the globe also face similar trend of noise (Table 6).

Table 6.

Comparison of noise levels with other studies.

Name of the city	Author name	Noise levels
Name of the city	Author name	L_eq	±SD	NC		LNP	TNI
Tiruchirappalli city	Nittala et al., (2014)	76.8	±4.3	14.7		X	X
Johor	Segaran et al., (2019)	75.4	X	X		86.9	80.8
Bankura city	Roy et al., (2019)	64.4	X	29.6		94.0	145.1
Basra city	Qzar et al., (2020)	72.4	±8.5	X		X	X
Hong Kong	Chan et al., (2015)	68.1	±6.3		X	X	X
Kholapur city	Hunashal and Patil (2012)	63.7	X		X	X	X
Kargil	This study	56.2	±8.5		14.1	70.3	89.6

The highest TNI value of 97.5 ± 7.6 dBA and NC value of 19.8 ± 2.3 dBA was recorded in the school located in the highway area; this was due to the fluctuation in the traffic flow rate along the highway during the daytime. Phukan and Kalita (2013) and Pradhan et al. (2016) in their studies in Guwahati and Angul Town also found that TNI and NC values were highest in areas located near the highway. While researching the effects of noise exposure on schoolchildren’s neurological behaviour, Kempen et al. (2010) discovered that children in schools near traffic or aircraft noise made more mistakes and performed worse on complex tasks. The Noise Pollution Level (LNP), which is considered to be the signaling cascade of noise limits for physiological and psychological disturbance of humans, also falls into the high-risk category of the EPA sensitivity standard of 65–70 dBA^53–55 in all the three schools, which indicates that the students in schools located in the commercial area and highway area are at greater risk. The poor acoustical conditions in all the schools were due to improper designing of school buildings, keeping only ventilation into consideration and lack of soundproofing. Aguilar and Tilano (2017) also found inappropriate architectural designs that only considered ventilation and ignored sound insulation, which caused poor acoustical performance in many schools in Medellin. In addition, noise levels of schools in Kargil town are also changing concerning the zones. The residential area bearing the lowest L_eq (52.9 dBA) was followed by the highway area (57.4 dBA) and the maximum L_eq was exhibited by the commercial area (58.3 dBA). Balashanmugam et al.⁵⁶(2013) and Patil and Nagarale (2013) in their studies of noise pollution in Chidambaram town and Nasik found changing noise with respect to different zones. The result clearly showed that noise pollution in Kargil town is associated with overcrowded traffic areas, haphazard road networking, construction of quiet zones (schools) in the main busy and noisy areas of the town, unplanned urban spreading, etc. Moreover, as the national highway passes through Kargil, the noise produced by the continuous stream of vehicles is also one of the factors contributing to noise pollution. The statistical Pearson correlation coefficient shows that only the schools located in the residential area show a significant positive correlation, which indicates that the outside noise is increasing significantly and affecting the indoor noise, but the other two schools show a positive but insignificant correlation. External noise influenced internal noise levels only when children were engaged in the quietest classroom activities and was not applied in current study. To determine sound level differences between the indoors and the outdoors for different window positions and how this sound damping is related to building characteristics could be an interesting focus for future studies.³² The performance of the students is closely related to the high level of noise, and it gets worsened when the schools are located near roads.²⁵ Abdullah et al. (2020) reported that 26% of students perceive road traffic noise to be disturbing, while some of them get disturbed by ringing bells and other noise in the vicinity of the school. According to Pakulski et al. (2016), children are much more impaired by noise than adults in listening and speech tasks. Around 72.4% of teachers in secondary schools in Italy believe that students of all age groups can perform better in quiet or low noise conditions than in a noisy environment.^57–59 Noise exposure should be controlled or minimised in schools, especially in primary schools and kindergartens.^60,61 According to Minichilli et al.⁶² (2018), annoyance characterization is a crucial step in developing awareness socially focused on the abatement of environmental noise effects and risks. Abdullah et al. (2020) suggested that to reduce the effect of environmental noise, relocating students to another class subjected to having lower noise levels but it’s not a permanent solution, so provision of the soundproof doors and insulated windows and doors for classes are a better option.

Conclusion

The nature of environmental noise in schools at the residential, commercial, and near the highway was significantly different. The LA_eq values observed for indoor and outdoor noise were alarmingly above the permissible limit of 35 and 45 dBA (WHO) 50 dB Central pollution control board (CPCB). The outdoor noise levels increased significantly at commercial and highway sites. TNI at the highway site exceeded the normal range. The local authorities and the school management should take the necessary steps to reduce the noise levels in schools. Several mitigations can be used to reduce exposure to environmental noise such as relocating the schools according to noise zonation mapping or relocating classwork to areas of the school that may potentially receive lower noise than class near the roadside, planting trees as noise buffers, and installing effective soundproof between the road and school. Aside from noise exposure assessment studies, there is a lot of room to evaluate the influence of noise on students' auditory systems, their performance, and the noise reduction strategies that are needed in various schools.

Footnotes

Acknowledgments

The authors thank to the school administration and the children for coordinating and helping with collecting data.

Authors’ contributions

KF collected the data, performed the statistical analysis and drafted the manuscript. MM helped to draft the manuscript and RKR participated in design of the study. KH helped in collection of data. All Authors have read and given final approval of the version to be published.

Declaration of conflicting interests

The authors declare that they have no competing interests. No funding was received for this study.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

Data availability statement

This manuscript outlines the source data used. Our results are available on special request.

ORCID iD

Kaneez Fatima

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