Assessment of noise pollution in and around a sensitive zone in North India and its non-auditory impacts

• Studied noise pollution and its non-auditory health impacts around a sensitive site • All sites have higher Leq than the permissible limit, during day and night hours • Highest SPL was recorded in ambulance vans (87-104 dB), which carries the patient • 74% respondents reported irritation, whereas 40.4% suffered noise induced headache • There is need to reduce noise through awareness, hospital engineering & acoustic measures ⁎ Corresponding author. E-mail addresses: khaiwal@yahoo.com, Khaiwal.Ravin http://dx.doi.org/10.1016/j.scitotenv.2016.05.070 0048-9697/© 2016 The Authors. Published by Elsevier B.V a b s t r a c t a r t i c l e i n f o


H I G H L I G H T S
• Studied noise pollution and its non-auditory health impacts around a sensitive site • All sites have higher L eq than the permissible limit, during day and night hours • Highest SPL was recorded in ambulance vans (87-104 dB), which carries the patient • 74% respondents reported irritation, whereas 40.4% suffered noise induced headache • There is need to reduce noise through awareness, hospital engineering & acoustic measures

G R A P H I C A L A B S T R A C T
a b s t r a c t a r t i c l e i n f o

Introduction
According to Florence Nightingale "Unnecessary noise is the most cruel abuse of care which can be inflicted on either the sick or the well" (Nightingale, 1992). Noise pollution in hospitals can impact sleep cycle, cardiovascular response, pain management, wound healing and other responses in a patient (Baker et al., 1993;Cohen, 1979;McCarthy et al., 1992;Sonnenberg et al., 1984;Stanchina et al., 2005;Topf and Davis, 1993;Topf et al., 1996;Wysocki, 1996). Cmiel et al. (2004) reported noise as a primary cause of sleep deprivation. Noise levels have also been shown to alter staff stress level, impact job performance, induce hearing loss at high noise levels, create annoyance and cause an increased rate of burnout (Bayo et al., 1995;Blomkvist et al., 2005;Love, 2003;Morrison et al., 2003;Norbeck, 1985;Zhang et al., 2012). Thus, noise pollution in hospitals is recognized as a serious health hazard and not just a nuisance.
World Health Organization (WHO) recommends continuous background noise in hospital rooms to be b35dB, with nighttime peaks in wards not to exceed 40 dB (Berglund et al., 1999). Although previous studies have reported high noise levels in hospital settings far exceeding permissible limits, little attention has been paid towards mitigating the hazards of noise pollution in hospitals. The objective of this study was thus to map the levels of noise pollution and explore the non-auditory effects of noise in a tertiary medical care institute in North India and thereby suggest measures to reduce noise and associated health impacts.

Methods
The study was conducted as per the guidelines of International Commission on the Biological Effects of Noise (ICBEN) for investigating noise levels, community response and its effects on the community. The study was conducted in an 1800-bedded tertiary hospital with a bed occupancy rate of 95% and more than 20 lakh outpatients annually. A total of 27 sites, outdoor, indoor, road side and residential areas were monitored for exposure to sound using Sound Level Meter (SLM). Envirotech (New Delhi) make Sound Level Meter (SLM100) was used in the current study considering its ease in field operations.
The SLM100 is a "Type 2" Integrating Sound Level Meter, which measure noise levels as dB(A). SLM was installed above 1.2 m using a tripod. Each location was monitored for 24 h including both day and night observations. The duration from 6 am to 10 pm was considered daytime whereas the time period from 10 pm to 6 am was referred as night time as per "The Noise Pollution (Regulation and Control) Rules, 2000". Sound level, diurnal pattern and weekend vs. weekday trend were also investigated. The indoor micro-environmental locations included emergency, intensive care unit (ICU), Trauma centre, library and other hospital buildings. The outdoor locations were parking areas, parks, shopping complexes, entrance gates etc., whereas the residential area included Doctor's Hostels and Staff quarters. Before visiting a location, the facility/location in-charge was informed about the purpose of the study and informed consent was taken before actually carrying out noise monitoring and the survey.
ICBEN questionnaire was adopted to conduct a detailed noise survey around the sampling site to know the perception of the exposed individuals (medical professionals, nurses, residents, patients, visitors, employees and other people in and around the institute campus) regarding the effect of noise in their daily life. Taking the prevalence of irritation/annoyance among exposed individuals as 40%, power of 95%, 10% absolute precision and non-response of 10%, a sample size of 100 was chosen (Basner et al., 2014). The inclusion criteria for selection of participants were: participants over 18 years of age, not using any ototoxic drugs, should not have any history of head injury, and no hearing loss. Ethical clearance for the project was taken from the Institute Ethics Committee, Post Graduate Institute of Medical Education and Research, Chandigarh, India. Table 1 depicts the individual source spectral analysis of noise. Surprisingly highest noise (sound pressure level) was recorded inside the ambulance van (87-104 dB), which carries the patient. It was observed that small ambulance van have privately fitted siren and hence have highest sound pressure level. Further, bus horn and security whistling also have sound pressure level above 90 dB. It appears that traffic inside the hospital (e.g. car, bus and two wheelers) dominate the environmental noise, whereas cleaning machine, television, ringing of phone and movement of trolleys dominate the indoor noise in the hospital. 3.2. Diurnal pattern of noise levels in and around the hospital As per 'The Noise Pollution (Regulation and Control) Rules, 2000', the day and night time ambient air quality standards in respect of noise are 50 dB and 40 dB, respectively, in India. Equivalent sound pressure level (L eq ) was found higher than the permissible limits at all the sites both during daytime and night. Maximum equivalent sound pressure level (L max ) during the day was observed higher (N 80 dB) at the emergency and around the main gate, Old hospital gate and OPD gate ( Fig. 1). L max during the night was higher (N 70 dB) at the emergency and around the main gate, old hospital gate and OPD gate, advanced cardiac centre, cafeteria, advanced pediatric centre and market area. Diurnal variation of sound level was maximum (N 10 dB) in locations such as school, residential area, in and around the main gate and the OPD gate, cafeteria, nursing institute and old hospital only during weekdays. Minimal diurnal variation (b 3 dB) was found in Library, hospital buildings like ICU-Advance cardiac centre and advance eye centre, Doctor's Hostel.

Weekday vs weekend noise pattern
Significant difference (10 dB) was observed between weekend vs weekday noise pattern at new OPD gate and old hospital during the office hours (Fig. 2). Noise pollution at main gate and OPD gate reduced only by 2 dB and 4 dB, respectively, during the daytime. Exceptionally high noise pollution was observed during weekend night at old hospital than weekday. No significant deviation was observed in noise levels at main Gate, OPD Gate at night during both weekdays and week nights.

Non-auditory impact of noise
All the respondents (100%) considered noise as a source of pollution (Table 2). More than half of the respondents were moderately sensitive to noise whereas 12.4% of them were highly sensitive to noise. Another 10.3% were very sensitive to noise. More than half of the respondents (55.6%) reported disturbance during sleeping due to noise. A total of 43.4% of respondents get disturbed during studying, whereas 38.4% of respondents feel disturbed during working hours due to loud noise (Fig. 3). Almost all the respondents (97%) regarded traffic as the major source of noise. About one-third of the respondents considered loud conversation, crowd and loud speaker as a major source of noise (Table 2). Loud music was perceived by 26% of respondents as a source of noise followed by construction work activities (16.2%), medical equipment (11.1%) and barking of dogs (11.1%). Nearly three-fourths (74%) of respondents reported irritation with loud noise, whereas 40.4% of respondents suffered from headache due to noise (Fig. 4). Less than one-third of respondents (29.3%) reported loss of sleep due to noise. On a scale of 0-10, traffic was considered as a major source of noise with a mean score of 6.8, followed by Air conditioners /Diesel generators (ACs/DGs, mean score: 4.9) as shown in Fig. 5. Table 3 shows a comparative overview of noise pollution monitoring and reported non-auditory health impacts in hospital settings. Based on Table 3, it can be concluded that sound levels in hospitals have always been found above the recommended levels, and ranges from 45 dB to above 120 dB. Similarly, the current work also observed noise levels well above the permissible standards at all the locations in and around a tertiary hospital. Further, movement of vehicles (traffic) was considered as the major source of noise.

Discussion
Regarding non-auditory health impacts of noise, respondents reported irritation, headache and loss of sleep due to increased noise levels. Hospital noise can pose problems for patient safety and recovery. Further, it may also contribute to stress and burnout among hospital workers. Grumet (1993) reported a significant correlation between increasing noise levels and increased length of stay and considered noise control in a hospital a high priority. The L eq in the current work exceed the recommended WHO guidelines at all the monitoring sities. The L eq was also found similar to sound levels observed in other healthcare settings as depicted in Table 3. Many of these studies have reported peak hospital noise levels exceeding 85-90 dB. Hospitals are noisy because of multiple sources of noise and surfaces in hospitals which tend to be sound-reflecting rather than sound-absorbing (Ulrich et al., 2004). The heavy inflow of patients along with visitors and traffic (engine noise, horns and public vehicles on adjacent roads) could probably be the major contributing factors for such high noise levels at the emergency, hospital buildings and around the gates. Other possible sources of noise include conversation among health care providers and visitors, moving carts, equipments and appliances (ACs, mobile phones, alarms of instruments, power generators). The lowest noise level during daytime was found at the library whereas during the night, the library, OPD on a holiday, school, residential areas and the Nursing Institute had lowest noise levels probably due to less crowding and restricted entry. Considerable diurnal variation (N 10 dB) was observed around the gates due to change in traffic flow pattern. Weekdays were found to be noisier than weekends, which might be attributed to less patient and traffic inflow during the weekends. Busch-Vishniac et al. (2005) showed that during the period 1960-2005, average day time noise in hospitals has increased from 57 to 72 dBA, whereas night time noise has increased from42 to 60 dBA, which is a major concern for patient safety and recovery.
In the present study, more than half of the respondents reported disturbanceduring sleeping due to noise. There are enough evidence in the literature, both subjective and objective, for sleep disturbance by the noise (Öhrström et al., 1988). More than 90% of respondents in the study stated that they get annoyed due to noise sometimes or always. Annoyance has been reported in the literature as the most widespread and well documented subjective response to noise, which may include fear and mild anger (Cohen and Weinstein, 1981). Noise is also associated with interference in daily activities, which leads to annoyance (Laszlo et al., 2012;Taylor, 1984). Irritation and headache have been reported by a large number of respondents similar to other studies (Öhrström, 1989). It has also been observed that the more sensitive to noise the individual was, the more frequent were these symptoms (Öhrström, 1989). The fact that more than three-fourth of the respondents in the present study reported moderate or higher sensitivity to noise, it is now ringing alarming bells to face this challenge headon rather than ignore this. The Nobel Prize Winner Robert Koch rightly predicted in 1910 that "One day man will have to fight noise as fiercely as cholera and pest". Less than one-third of respondents reported loss of  sleep due to noise. Sleep deprivation has wide-ranging effects on the cardiovascular, endocrine, immune, and nervous systems causing obesity, diabetes and impaired glucose tolerance, cardiovascular disease and hypertension, anxiety disorders and depressed mood (Colten and Altevogt, 2006). Hence, non-auditory effects studied in the current work can add to the risk factors associated with non communicable diseases. Further, the recent Global Burden of Disease also highlights the increasing risk of non communicable diseases. Whereas, quiet time and improved acoustics reduces noise levels, improves sleep and have a positive impact on work environment and job strain.

Recommendations
Studies have shown that installing sound-absorbing ceiling tiles and panels results in reduced noise levels and perceptions of noise leading to improved speech intelligibility and reduced perceived work pressure among staff (Blomkvist et al., 2005;MacLeod et al., 2007). Single-bed rooms are probably the single most-effective strategy for reducing noise in wards (Joseph and Ulrich, 2007). Some hospitals have installed a device like a traffic light that monitors the noise level by turning from yellow to red as it rises. "Quiet Kits" with sleep masks and earplugs help patients tune out intrusive sound. Kahn et al. (1998) determined that 51% of the noise in the ICU was modifiable. He later found that by implementing simple behavior modification strategies through educational sessions and other simple measures such as metal bins replaced with plastic significantly reduced the peak noise level. A study by Ramesh et al. (2009) conducted in a tertiary hospital in India mention that simple environmental modification like fitting legs of all furniture with rubber shoes, replacing all metallic files with plastic files, keeping the phone ringer at a minimum audible level reduced the noise level significantly. Quiet time, a period of reduced controllable noise and light at preset intervals was found to significantly reduce noise levels and increase sleep hours (Dennis et al., 2010;Olson et al., 2001). Simple measures like keeping equipments and alarms away from patients, switching mobiles phones to vibrating or low volume mode, providing signs like "Quiet please", awareness programs for staff help reduce noise (Bremmer et al., 2003). Music therapy has also been shown to have a beneficial impact on patient anxiety and a host of other physiological parameters (Cabrera and Lee, 2000). Thus, a combination of behavioral modification, administrative and engineering controls may reduce noise levels below the recommended level.

Research gaps
More research is needed to establish which noise interventions are most likely to reduce noise levels and produce favorable medical outcomes. Research is also needed to bring out ways of reducing noise through engineering of hospital structures and acoustic measures. As highlighted by Ravindra et al. (2015), air pollution is becoming an emerging public health issue due to increasing evidence of poor air quality and adverse human health effects. Hence, there is a need to investigate that how noise pollution synergistically add to the effect of air pollution.

Conclusions
Noise levels monitored in and around a sensitive site are well above the permissible standards. To effectively tackle hospital noise, awareness of health care staff and public is needed. There are easily modifiable sources of noise which hospitals should identify to reduce noise and its Operating rooms, USA Sound levels Highest with orthopaedic surgeries-66 dB, peak N 120 dB Kracht et al., 2007 Post anaesthesia care unit Sound levels and sources of noise Mean 67 dB, L eq max 76 dB, L eq min 49 dB, staff conversation caused maximum noise Allaouchiche et al., 2002 Tertiary care hospital, Taiwan Sound levels and sources of noise 50-68 dB in wards, b50 dB during night in surgical ICU, 98-108 in generator rooms and AC facilities Pai, 2007 Neonatal ICU, USA Sound levels L eq (60.44 dB range of 55-68 dB) and L max (M = 78.39, range = 69-93 dB) Krueger et al., 2005 Tertiary care hospital, North India Sound pressure levels, individual source spectral analysis of noise, perceived non-auditory impact of noise, impact of noise on routine activities, diurnal pattern, weekend vs weekday pattern Ambulance, bus horn and security whistling had the highest noise, significant diurnal and weekend vs weekday variation. L eq N 80 dB during daytime and N70 dB during night in most sites. Traffic-major source of noise, patients reported irritation, headache and loss of sleep due to noise Present study impact on health. This will help mitigating the increasing risks associated with non-communicable diseases as the non-auditory effects add to the risk factors associated with these diseases. Further, reduction in noise will provide a more pleasant and peaceful environment for patients and staff.