Assessment of Citizens Perception towards Traffic Noise Induced Hearing loss in Dhaka City Dr. Ahmad Kamruzzaman Majumder Lecturer Department of Environmental Science Stamford University Bangladesh 744, Satmasjid Road, Dhanmondi Dhaka-1209, Bangladesh Tel: +88 02 8153168-69, +88 02 8156122-23, +88 02 8155834 Ext.-338. Fax: +88 02 8119956, +88 02 9143531. Mob: +88-01712017725, +88-01816145191 E-mail: kamrul_sub@hotmail.com, kamrul_subd@yahoo.com K. M. Nazmul Islam Lecturer Department of Environmental Science Stamford University Bangladesh 744, Satmasjid Road, Dhanmondi Dhaka-1209, Bangladesh Tel: +88 02 8153168-69, +88 02 8156122-23, +88 02 8155834 Ext.-338. Fax: +88 02 8119956, +88 02 9143531. Mob: +88-01198205344, +88-01558615741 E-mail: kmni_noyon@yahoo.com, noyon.ifescu@gmail.com Professor Dr. K. Maudood Elahi Chairman Department of Environmental Science and Pro-Vice Chancellor Stamford University Bangladesh. 744, Satmasjid Road, Dhanmondi Dhaka-1209, Bangladesh Tel: +88 02 8153168-69, +88 02 8156122-23, +88 02 8155834 Ext.-298. Fax: +88 02 8119956, +88 02 9143531. Mob: +88-01819426088 E-mail: elahikm@stamforduniversity.edu.bd Jussi Dayna Biswas Lecturer Department of Environmental Science Stamford University Bangladesh 744, Satmasjid Road, Dhanmondi Dhaka-1209, Bangladesh Tel: +88 02 8153168-69, +88 02 8156122-23, +88 02 8155834 Ext.-338. Mob: +88-01717143313 E-mail: diana_jussi2005@yahoo.com Banasree Paul Graduate Student Department of Environmental Science Stamford University Bangladesh 744, Satmasjid Road, Dhanmondi Dhaka-1209, Bangladesh Tel: +88 02 8153168-69 Mob: +88-01717290127Page 1 of 15

Assessment of Citizens Perception towards Traffic Noise Induced Hearing loss in Dhaka City ABSTRACT This paper aims to measure the traffic noise at the different spots adjacent to Sahabug area of Dhaka city in four different times as day, noon, evening and night. The noise levels were measured with the help of a portable precision digital sound level meter. To evaluate the Noise Induced Hearing Loss (NIHL) an AC33 classic two-channel clinical audiometer has used. A large number of Hawkers and Shopkeepers were present in the study area but 50 hawkers and shopkeepers were considered for this study on the basis of some selecting criteria. Again to know about the citizens perception towards traffic noise pollution in Dhaka City perception study has carried out by a questionnaire administered to 100 individuals including vehicle drivers, hawkers and shopkeepers in Sahabug Area. It is being observed from the study that, the sound level is minimum for the third Monday during the day time and maximum at the first Monday of that month at the day time which was 68 dB (A) and 85 dB (A) respectively. The survey showed people exposing to noise of that area are highly suffered from Mild type of hearing loss in the right ear with a number of 55%. From the perception study it is found that, 60% respondents were not satisfied about the noise level in their place. Headache, bad temper, hearing problem, loss of concentration were some of the significant effects manifested by noise pollution. Keyword: Environment, noise pollution, health hazard, Audiometric test. INTRODUCTION The hazardous effects of noise on hearing have been of interest for over a century. Over the past few decades we have gained considerable in sight into the mechanisms and features of noise-induced hearing loss (Humes, 1984). Noise Induced Hearing Loss (NIHL) is a significant social and public health problem. With global urbanization, there are many environment problems causing pollution and environmental degradation. Out of many environmental problems, noise has emerged as one of major urban environmental pollution (Joshi et. al., 2003, Majumder et.al., 2010). Adult-onset hearing loss has been described as the 15th most serious health problem in the world and it is the second most common type of hearing loss after presbyacusis (old age associated hearing loss), and all age groups can be affected, with profound effects ranging from social isolation and stigmatization of individuals to serious national economic burdens (Smith, 2004).Page 2 of 15

Estimates of the number of people affected worldwide by noise induced hearing loss increased from 120 million in 1995 to 250 million worldwide in 2004 (WHO, 1999; WHO, 2001; WHO, 2002; WHO, 2004; Smith, 2004). Summary statistics on traffic noise exposure are not available for most of the countries; however, high occupational noise exposure levels were reported in 17 studies conducted in 12 countries in South America, Africa, and Asia. In these studies high traffic noise pollution have reported. Many of these studies reported hearing losses in exposed person. Worldwide, 16% of the disabling hearing loss in adults is attributed to noise pollution. The effects of the exposure to noise pollution are larger for males than females and higher in the developing countries (Nelson, et. al., 2005). Road traffic noise is a major source of noise in urban areas (Majumder, et.al., 2007). It produces disturbance and give an impact to more people than any other forms of noise source (Dix, 1981). Noise induced hearing loss is of a sensory neural type involving injury to the inner ear. Hearing loss usually refers to hearing impairment that is causing difficulties or to a hearing threshold level that has deteriorated (King, 1992). Hearing loss can be caused in number of ways due to rupture of eardrum, breaking of the bones in the middle ear etc. Prolong noise exposure to high intensity sound can damage the hair cells of the inner ear leading to permanent hearing loss (Harrison, 2008). The audiogram observed in cases of noise induced hearing loss is characterized by an onset of hearing loss at 4000 Hz, visible as a dip in the audiogram. As exposure to excessive noise levels continues, neighboring frequencies are progressively affected and the dip broadens, encroaching at approximately 3000 Hz. Noise induced hearing loss is usually bilateral and shows a similar pattern in both ears (Joshi et.al., 2003).

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Figure 1: Audiogram showing bilateral noise-induced hearing loss (source: Joshi et.al, 2003)

A number of studies related to noise induced hearing loss in Human have been conducted around the world (Banerjee and Chakraborty, 2006; Chakraborty et al.,2002; Chung et. al., 2005; Nelson et. al.,2005; Harrson, 2008; Joshi, et. al., 2003; Murthy, et. al.,2007; Nirjar et al., 2003; Thakur, 2006). But in Bangladesh most of the work is related to noise pollution assessment. Therefore the main objective of the study was to find out environmental noise induced health effect on people exposed to noise pollution and to know the people perception regarding noise pollution. MATERIALS AND METHODS Traffic Noise Pollution Monitoring The traffic noise measured at the different spots adjacent to Sahabug area of Dhaka city in four different times as day(9-12 pm), noon(12-3 pm), evening (3-6 pm) and night (6-9 pm) are shown in Table-1, 2, 3 and 4. The area comprises Bangabandhu Seikh Mujib Medical University (BSMMU), Birdem hospital, Sheraton Hotel, National Museum, Public library, Charukola Institute, Shisu park, Tennis Federation, Shopping mall and a number of important office. There were in all 10 locations which are commercial in nature and as such Sahabug area is a commercial hub of Dhaka. The noise levels were measured with the help of a portable precision digital sound level meter (Model- ST8850, made in England). This instrument is primarily designed for community noise surveys. A large digital display gives a single value indication of the maximum A weighted RMS (root mean square) sound pressure level measured during the previousPage 4 of 15

second. Measurements from 30 to 135 dB (A) can be carried out with this instrument. The instrument calibration was achieved using manufacturer supplied calibrator capable of producing known sound pressure level. Noise measurements were taken following the prescribed procedure stipulated in the manual of the manufacturer of Sound Pressure Level meter. The data was collected above 1.5 meter of the ground and the data was taken by standing on the roadside. Any kind of noise barriers was avoided for measuring the actual sound level produced by the vehicles. The results were filled in at the spot of measurement in pre-designed formats. Audiometric Test To evaluate the Noise Induced Hearing Loss (NIHL) an AC33 classic two-channel clinical audiometer has used. In the audiometer a wide range of input and output selections are available ensuring flexible choices in test stimuli and transducer combinations including the mixing of speech and noise which is a popular combination for hearing aid evaluations. The patient wares a head phone which is connected with the clinical audiometer. The audiologist press button of sound of various frequencies (low to high) one by one. The patient also holds a button. When he hear the sound then he press the button and he does not press when he does not hear. According to the response of the patient audiologist note down the frequencies and audiometric report is prepared. A large number of Hawkers and Shopkeepers were present in the study area but some Hawkers and Shopkeepers were considered on the basis of some selecting criteria as: People has not been affected by any kind of ear related disease since childhood to till now, people whose age in between 20 to 50 years, people who are working more than 5 years in this place and people who work here more than 9 hours daily. Questionnaire Survey To know about the citizens perception towards traffic noise pollution in Dhaka City perception survey carried out by a questionnaire administered to 100 individuals including vehicle drivers, hawkers and shopkeepers in Shahbag Area. For our study we took Hawkers and shop keeper as a sample because they are directly exposed to the noise. The people who work in BSMMU, BIRDEM, and National Museum etc are remain inside the building so they are not affected by noise severely. The people (come to visit the patient), the students and travelers are not permanently exposed in such noise. They occasionally visit the area. Thats why Hawker and shop keeper are the primePage 5 of 15

consideration as a sampling group because they remain beside the road and they are directly exposed to the traffic noise. RESULTS AND DISCUSSION Traffic Noise Pollution Table 1 summarized the analysis of noise pollution assessment data, recorded in different day times of Monday, Tuesday and Wednesday in a month. It is being observed from the study that, the sound level is minimum for the third Monday during the day time and maximum at the first Monday of that month at the day time which was 68 dB (A) and 85 dB (A) respectively. Considering Tuesday at the day time the study have shown that, the sound level was minimum at the first and second Tuesday of the month whereas the maximum sound level was recorded at the second Tuesday that was 70 dB (A) and 82 dB (A) respectively. The minimum level of sound for Wednesday was recorded at the second Wednesday and the highest level was recorded at the third Wednesday of the month showing the value of 69dB (A) and 84 dB (A) respectively. The study also enlighten the fact that, during day time Monday 2 posses the minimum record of noise level and Monday 1 posses the highest level of noise record with the value of 68 dB(A) and 85 dB(A) respectively. The highest minimum and maximum noise levels observed at the day during Monday, Tuesday and Wednesday in a month are 78 dB (A) and 85 dB (A), 76 dB (A) and 82 dB (A) , 74 dB (A) and 84 dB (A), respectively, whereas the permissible level for road traffic noise is 70 decibels dB (A) (Murthy et. al., 2007). The source is predominantly attributable to motor vehicular traffic. The min dB(A) of 9 days record, adjacent to the Sahabug area, has bested the permissible limit except Monday 2 and Wednesday 2, in the survey month (Table-1). Table-1: Sound level with respect to time in Day for one Month. Time Days in the Month Monday 1 Monday 2 Monday 3 Tuesday 1 Tuesday 2 Tuesday 3 Wednesday 1 Wednesday 2 Wednesday 3 N Sound Pressure levels, dB(A) Min Max 78 85 68 83 73 80 70 75 70 82 76 70 74 82 69 76 72 84 Highest record in a month, dB(A) Min Max 68 85

9-12 pm (Day)

10 10 10 10 10 10 10 10 10

70

82

69

84

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N= number of observation Table 2 summarized the analysis of noise pollution assessment data, recorded in different noon times of Monday, Tuesday and Wednesday in a month. The lowest sound level for Monday of the month was recorded at Monday 1 which was 56 dB (A) and the highest sound level was recorded at Monday 2 and as well as for Monday 1 that is 83 dB (A) at the noon time. The minimum sound level recorded at the month for Tuesday was observed in the Tuesday 1 which was 59 dB (A) and the maximum value was 73 dB (A) in the Tuesday 3 at the noon time of that particular month. The minimum level of sound was recorded for Wednesdays of the month at the noon was in Wednesday 2 with the value of 59 dB (A) and the maximum level was in the Wednesday 3 with the value of 73 dB (A). the values suggested that, lowest level of sound recorded among the sampled days was on Monday 1 with value of 56 dB(A) and the highest level of sound were recorded on both Monday 1 and 2 having a value of 83 dB (A) for the noon (12-3pm)The highest minimum and maximum noise levels observed at the day during Monday, Tuesday and Wednesday in a month are 59 dB (A) and 83 dB (A), 68 dB (A) and 73 dB (A), 68 dB (A) and 73 dB (A), respectively. In different times of noon the min dB (A) of 9 days record, adjacent to the Sahabug area, is lower than the permissible limit, during the survey month. However, all the Max record exceeds the permissible limit (Table-2). Table-2: Sound level with respect to time in noon for one Month. Time Days in the Month N Sound Pressure levels, dB(A) Min 56 58 59 59 68 63 68 59 68 Max 83 83 82 70 71 73 72 71 73 Highest record in a month, dB(A) Min 56 Max 83

12-3 pm (Noon)

Monday 1 10 Monday 2 10 Monday 3 10 Tuesday 1 10 Tuesday 2 10 Tuesday 3 10 Wednesday 1 10 Wednesday 2 10 Wednesday 3 10 N= number of observation

59

73

59

73

Table 3 summarized the analysis of noise pollution assessment data, recorded in different evening times of Monday, Tuesday and Wednesday in a month. Form the study it has been observed that the minimum sound level was recorded on Monday 3 and thePage 7 of 15

maximum level was recorded for Monday 1 for one month at the evening hours( 3-6 pm), which were 66 dB (A) and 77 dB(A) respectively. The minimum sound level recorded in the value of 67 dB (A) was observed on Tuesday 2 and the maximum sound level in the value of 82 dB (A) was observed on Tuesday 2 for one month during the evening hours (3-6 pm). The minimum level of sound recorded for one month at the evening hours (3-6 pm) in Wednesday was at Wednesday 1 having the value of 68 dB (A) whereas the maximum value was 82 dB(A) also recorded on Wednesday1 . among the observed days Monday 3 posses the minimum level of noise having a value of 66 dB (A) and both Tuesday 2 and Wednesday 1 showed the highest record of noise level with a value of 82 dB(A). The highest minimum and maximum noise levels observed at the day during Monday, Tuesday and Wednesday in a month are 69 dB (A) and 77 dB (A), 70 dB (A) and 82 dB (A), 70 dB (A) and 82 dB (A), respectively. In the evening all the min dB(A) of 9 days record, is lower than the permissible limit, during the survey month, except Tuesday 1, Tuesday 3, Wednesday 2. However, all the Max record exceeds the permissible limit (Table-3). Table-3: Sound level with respect to time in evening for one Month. Time Days in the Month N Sound Pressure levels, dB(A) Min 69 69 66 70 67 70 68 70 70 Max 77 75 73 73 82 75 82 79 76 Highest record in a month, dB(A) Min Max 66 77

3-6 pm Monday 1 (Evening) Monday 2 Monday 3 Tuesday 1 Tuesday 2 Tuesday 3 Wednesday 1 Wednesday 2 Wednesday 3 N= number of observation

10 10 10 10 10 10 10 10 10

67

82

68

82

Table 4 summarized the analysis of noise pollution assessment data, recorded during different night times of Monday, Tuesday and Wednesday in a month. The minimum sound level recorded for the month on Monday was 53 dB (A) on Monday 1 and the maximum sound level was recorded as 66 dB (A) on Monday 2 during the night time (69pm). The minimum sound level observed for the month was on Tuesday 3 and the maximum sound level recorded was on Tuesday 1 and the values were 50 dB (A) and 68Page 8 of 15

dB(A) respectively during the night time (6-9pm) for one month . The minimum noise level recorded in the value of 52 dB (A) on Wednesday 2 and the maximum noise level was observed on Wednesday 1 with the value of 68 for one month during the night time (6-9pm). Among the total exemplified days Tuesday 3 have the minimum value of the noise level with the value of 50 dB(A) whereas the maximum value was shown on both Tuesday 1 and Wednesday 1 with a value of 68 dB(A) during the nights (6-9pm). The highest minimum and maximum noise levels observed at the day during Monday, Tuesday and Wednesday in a month are 57 dB (A) and 66 dB (A), 56 dB (A) and 68 dB (A), 59 dB (A) and 68 dB (A), respectively. In the night all the min and max dB(A) of 9 days record, is lower than the permissible limit, during the survey month (Table-4). Table-4: Sound level with respect to time in night for one Month. Time Days in the Month N Sound Pressure levels, dB(A) Min 53 57 55 51 56 50 59 52 57 Max 62 66 64 68 63 61 68 64 67 Highest record in a month, dB(A) Min 53 Max 66

6-9 pm (Night)

Monday 1 10 Monday 2 10 Monday 3 10 Tuesday 1 10 Tuesday 2 10 Tuesday 3 10 Wednesday 1 10 Wednesday 2 10 Wednesday 3 10 N= number of observation

50

68

52

68

Noise Induced Hearing Loss and perception of the Respondents Noise has the potential to damage the hearing cells of the cochlea in the inner ear (Chung et. al., 2005). Figures 2 and 3 show what can happen to the delicate hair cells of the cochlea of ear due to consistent exposure to noise pollution resulting into noise induced hearing loss or acoustic trauma (Harrison, 2008). The organization of normal hair cells (stereocilia) is showed in the figure 2. These stereocilia, when deflected by acoustic signals cause an excitation or depolarization of the hair cell, resulting into neural activity in cochlear afferent neurons that make up the auditory nerve (Chung et. al., 2005). For each cell, the stereocilia are neatly organized in a bundle (left panel of figure 2). The individual hairs are cross-linked, and when the whole bundle is displaced by sound signals, some of these links pull open membrane ion channels on the surface of the hairs. Flow of ions (mainly potassium) though these membrane channels change the hair cellPage 9 of 15

receptor potential (Mathur and Roland, 2009). These entire micromechanical arrangements and linkages of stereocilia, and the membrane ion channels are delicate gradually damaged due to constant exposure to noise pollution (Harrison, 2008). Some of the first obvious signs of acoustic over-stimulation are illustrated in figure 2. The stereocilia appear to loose their rigidity and become splayed apart (right panel of figure 2). Clearly when this happens the linkages between the hairs are broken and can no longer mediate the opening and closing of membrane ion channels; the hair cells can no longer work as sensory receptors (Mathur and Roland, 2009). The cells cannot recover from this state, and soon after this degree of damage, the cell self-destructs resulting into noise induced hearing loss or acoustic trauma (right panel of figure 3). The stereocilia start to be digested back into the cell and there is no recovery (Harrison, 2008). Noise induced hearing loss -immediate effectsEarly stages of hair cell damage after acoustic trauma

Normal sensory epithelium

Figure-2: Scanning electron images illustrating normal cochlear hair cells (left) and immediately after noise trauma (right). The lower left diagram shows the normal linkages between stereocilia that are disrupted or broken in noise induced hearing loss (Source: Harrison, 2008). Noise induced hearing loss hair cells dyingHair cells degenerating after damage by noise trauma Page 10 of 15

Normal cochlear hair cells Figure-3: The stereocilia of healthy cochlear hair cells (left) compared with cells after acoustic trauma, and in the process of complete degeneration (right). There is no natural regeneration of hair cells in the mammalian cochlea (Source: Harrison, 2008).

Table 5 summarized the analysis of Noise induced hearing loss of the respondent, in the shabug area of Dhaka city for 50 respondents. The survey showed people exposing to noise of that area are highly suffered from Mild type of hearing loss in the right ear with a number of 55%. People while suffer from the least problem of Moderate type of hearing loss in the left ear with the percentage of 24 of that particular area. It also can be said that the second highest percentage of peoples suffering is from mild of hearing loss in left ear with the value of 45. Other then these 28% people of the area suffer from Moderate type of hearing loss in right ear, 30% suffer from moderate type of hearing loss in both ear, 25% suffer from sever type of hearing loss in left ear and 27% suffer from severe type of hearing loss in right ear. Form the study it can emphasized on the fact that, people adjacent the area use to suffer from various level of hearing loss in both ears which varies from mild to severe level.

Table 5: Noise induced hearing loss of the respondent Noise Induced hearing loss Mild type of hearing loss in left ear Mild type of hearing loss in right ear Moderate type of hearing loss in left ear Moderate type of hearing loss in right ear Moderate type of hearing loss in both ear Severe type of hearing loss in left ear Severe type of hearing loss in right ear Percentage 45 55 24 28 30 25 27Page 11 of 15

The noise perception survey carried out by a questionnaire administered to 100 individuals in Sahabug area indicated that most of the people including vehicle drivers were aware about noise pollution but their health significance was not fully realized. 60% respondents were not satisfied about the noise level in their place. Headache, bad temper, hearing problem, loss of concentration were some of the significant effects manifested by noise pollution. Weighted complaints of the respondents intended to different psychological and physical effects induced by the noise are shown in the table 6. The foremost health effect tempted by the noise pollution was observed as Headache. Irritation, Hard hearing and Lack of Concentration were also other major health effects caused by noise pollution. Chest pain and nausea were the slightest health effects perceived conferring to the respondents. The general public strongly supported actions from the government to reduce noise pollution, many supporting the ban the hydraulic horn, improved traffic control, banning very old vehicles, banning high-noise creating industries such as stone crushing machines right inside urban areas, zoning according to noise ranges, and banning usage of public audios line sound amplifying mikes for processions, advertising, and election campaigns. Table 6: Respondents weighted complaints on health effects related to noise. Respondents complaints related to Noise Lack of Concentration (decreased performance) Dizziness Chest Pain Nausea Sleep Disturbance Headache Speech Disturbance Hard hearing Fatigue Irritation CONCLUSIONNoise pollution is an interfering air-pollutant which possesses both auditory and a host of nan-auditory effects on the exposed population. Since there is no medicine to cure hearing loss prevention to overt exposure is the only alternative left. The hawkers and shopkeepers

Percentage 49 27 14 12 37 55 24 43 30 46

were considered for this study on the basis of some selecting criteria. Again to know about the citizens perception towards traffic noise pollution in Dhaka City perception study has carried out by a questionnaire administered to 100 individuals including vehiclePage 12 of 15

drivers, hawkers and shopkeepers in Shahbag Area. It is being observed from the study that, the sound level is minimum for the third Monday during the day time and maximum at the first Monday of that month at the day time which was 68 dB (A) and 85 dB (A) respectively. The survey showed people exposing to noise of that area are highly suffered from Mild type of hearing loss in the right ear with a number of 55%. People while suffer from the least problem of Moderate type of hearing loss in the left ear with the percentage of 24 of that particular area. The perception survey indicate high prevalence of headaches, lack of concentration, sleep. Since levels lie much above the prescribed limits there is an imminent health risk to the exposed population and the study suggests control measures to be instituted on a priority.

ACKNOWLEDGEMENTSThe authors are thankful to the Department of Environmental Science and administration of Stamford University Bangladesh for their support to carry out this study.

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