International Journal of Environmental Research University of Tehran ISSN: 1735-6865 EISSN: 2008-2304 Vol. 3, Num. 4, 2009, pp. 645-652

International Journal of Environmental Research, Vol. 3, No. 4, 2009, pp. 645-652

Effects of Noise Pollution on Traffic Policemen

Omidvari, M. ¹ and Nouri, J. ^2*

¹Department of Industrial & Mechanical Engineering, IA University, Qazvin, Iran
²Department of Environmental Management, Graduate School of the Environment & Energy, Science & Research Branch, IA University, Tehran, Iran
*Corresponding author E-mail: nourijafar@gmail.com

Received 7 Nov. 2008; Revised 12 Jan. 2009; Accepted 13 March 2009

Code Number: er09070

ABSTRACT

Noise pollution can be considered as the most important problem of urban environmental management in mega metropolises and urban transportation is the main source of the mentioned problem. This study aims to investigate the amount of traffic noise dose received by traffic policemen in Tehran; District 1 Municipality. The investigation was conducted during three consecutive months in 2007 in 282 locations of the main streets of studied district which are known for its heavy traffic, as well as population flow. In order to measure the noise volume, pre-calibrated Cell – 450 and Quest –2900 sound level meters were used. Regarding to noise dosimeter, 158 cases were measured using a dosimeter Cell-320. For this purpose, L, L, L and L indicators were used. The results showed that the L _eq average during peak traffic load hours and in the least traffic conditions was 77.2 ± 2.1 and 64.5 ± 2.2 dB, respectively which were higher than the acceptable levels (55dB). Moreover, the statistical results showed the significant differences between light and heavy traffic conditions and also the direct effect of heavy traffic on noise pollution, also it was shown that vehicles traffic is the main source of the produced noise pollution. The study created a related questionnaire which evaluated the traffic policemen behavior from them and their relative’s point of views. The results showed that noise pollution has damaging effects on their behavioral conditions and also, on their personal assessment. The policemen believed their psychological disorders and their relative had also the same opinion. This study attempted to show that noise pollution in metropolises such as Tehran is a serious problem and it is should be treated as a top priority in the urban environmental management in order to reduce noise pollution.

Key words: Heavy traffic, Metropolis, Noise dose, Urban environnemental management

Nowadays, noise pollution is considered as one of the main problems of urban communities which has many hazardous effects on the urban environment and may result in a great deal of costs on the society (Martin et al., 2006; Chien and Shih, 2007).) and traffic can be considered as the main source of noise pollution in large cities (Jamarah et al., 2006 and Murthy et al., 2007). According to the researches, noise pollution caused by traffic is one of the major problems in the southern large cities of Sweden (Skanberg and Ohrstrom, 2002 and Bjork et al., 2006). In another research conducted in 2004 in the same country, in addition to mentioning the problems of noise pollution in the big cities of Sweden, the researchers have demonstrated that noise effects will limit the episodic memory (Enmarker, 2004). The traffic policemen in metropolises are the most affected groups exposed to this dangerous factor during their working hours and in their leisure time. Ingle et al. (2006) have been measured the noise dose received by this group as 88 dB and, in some cases, it has been increased up to even 100 dB (Ingle et al., 2006). Statistic results published by Organization for Economic Co-Operation and Development (OECD) in 1994 specified that more than 17 million people in France are exposed to sounds louder than 55 dB during 8-20 hours of their lives, whereas the minimum standard noise for noise pollution in the environment is 55 dB (Banerjee et al., 2009). Canadian hearing society (CHS) researchers had considered urban environment as crowded, busy and noisy. Jackhammers pounding, sirens whining, alarms ringing, subway trains screeching, aircraft zooming overhead, car horns honking are a few of the annoying and potentially hazardous sounds face to dwellers. Moreover, it was concluded that the noise in some parts of these cities is so much that can lead to long-lasting and irrecoverable effects on the citizens and in places like masonry workshops and may increase above 100 dB. In this article, the traffic noise was measured as 89 dB, the car horns as 97 dB and the shopping centers as 81 dB. Regarding to the sound standards (less than 55 dB) determined by World Health Organization (WHO), studying of the urban environmental noise became significant (Banerjee et al., 2009). Another research conducted in Spain showed that the noise pollution resulting from traffic is one of the main problems of the small and non-industrial cities (Barrigon et al., 2002). Jacov et al. (2006) and Muzet et al. (2007) were also studied the effects of noise on the citizens sleep condition. In these researches, the minimum level of noise volume during day and night was measured as 65 and 55 dB, respectively. Meanwhile, it was designated that people who live in crowded areas suffer sleeping disorders (Jakovljevic et al., 2006 and Muzet, 2007). Piccolo (2004) stated that the amount of sound in Messina is higher than normal. Thus, the urban environmental noise must be studied (Piccolo et al., 2004). As stated in a report, a relatively high percentage of people considered the noise pollution as the biggest problem in London metropolis where the traffic noise has been selected as the main noise source by 23 % of people (Pathak et al., 2008). Guite et al. (2006) studied the effects of urban environment over the public health and wellbeing and they concluded that the environmental noise can affect the mental health (Guite et al., 2006). In a similar research conducted in Spain, it was demonstrated that the noise resulted from traffic can lead to physical and mental effects on the individuals (Vera et al., 1992). Li et al. (2002) stated that the speed of the vehicles, the traffic load, the number of trucks and the road surface were also the main factors of traffic noise in Beijing (Li et al., 2002).

Regarding to the number of vehicles and the traffic load among the rich habitants of the district one of Tehran and by means of traffic organization and traffic police center data of the mentioned district, the traffic situation and the number of traffic policemen residing in the area were identified and their location were spotted. Then, the places that the measurement was supposed to carry out were located by means of available municipal maps taken from the traffic organization and also using four sound level meters (CELL450 and Quest-2900) and the amount of which L_eq, L₁₀ , L_-max and L_-min were measured. All themeasurements were done in the peak of traffic during three months in the highest and the lowest traffic jam. Measurements were performed at a distance of zero from the signal stop line. The traffic jam and composition was taped using a video camera. The traffic jam during the measuring time was categorized into four groups and was recorded in information cards. In each measuring period, 141 cases were measured and altogether 282 locations in the main streets of the district were recorded, which are shown in Fig. 1. A significant difference between the level of noise dose received by traffic policemen in the minimum and the maximum traffic load was recorded (P < 0.05).

In the next step, in order to measure the level of noise dose received by the traffic policemen, the measurement was done according to the shortterm standard and the data collected from analysis of the traffic policemen job in a short-term period (1 h). The applied instrument for this research was CELL-320 for the noise pollution dosimeter. The measurements were accomplished using the dosimeters attached to the body of the policemen. After determining the work stations and directions and also, the time spent at each station, the system was installed on the direction for the considered time lag and the results were recorded. For this purpose, 79 cases were measured in each period of time and in two particular times; before and after the Iranian New Year, Norouz, in 2006.

Furthermore, a questionnaire, as shown in Table 1, was distributed amongst the elected policemen containing questions about their personal characteristic and moods. Also, some questions were designed to be answered by their relatives, in order to evaluate the traffic policemen’s moods. All the measurements were done on the side of one-way streets, just between the side-walk and the main street. In the two-way streets, this measurement was done on both sides of the street. In this research, the statistics such as mean and standard deviation for descriptive statistics methods were used. Regarding to the dependence of these samples on each other in different traffic conditions for demonstrating traffic effects on noise level, T-Test-paired method was used and statistical calculations were done by SPSS software.

The residents of the studied district were asked about the most important environmental problems which might have the highest effect in their lives. According to the final results, 45 % considered traffic as their most important problem. Furthermore, 43 % believed that the main trafficrelated problem was sound pollution. The mean level of L _eq during the peak and the least hours of traffic in the streets were 76.6 ± 1.8 dB and 67.6 ± 3.1, respectively as shown in Table 2. According to the changes in the streets and traffic conditions, the statistical results showed that there was a significant difference between the heavy and light traffic (P < 0.05). In order to study the environmental noise and its level in the main streets of the mentioned district, which is shown in Table 2, L₁₀ was calculated. The mean and standard deviations in L₁₀ were calculated as 75.5 ± 1.7 (before Norouz) and 66.8±3 (after Norouz) in the heavy and light traffic, respectively. The statistical results showed that there was a significant difference between the minimum and maximum traffic load (P < 0.05), while the level of LP_max measured in the minimum and maximum traffic flow shown in Table 2. As it can be seen in this table, the mean level of LP_max throughout the area was about 97.1 ± 4.3 during the maximum traffic (before the Norouz) and about 86.7±2.9 during minimum traffic flow which showed the high noise level in the studied district. According to statistical results, there was a significant difference between the Lp_max in various states of the traffic load (P > 0.05). The other factor studied in this research was the level of LP_min which was measured at the maximum and minimum traffic load as shown in Table 2.

The results can be considered as not being acquainted with the environmental noise. However, it was demonstrated that this phenomena had some effects on the personal characteristics and nervousness of the individuals as social consequences; therefore, importance of noise controlling management should be taken into considerations. It should be mentioned that the effects of noise on the cyclist policemen was less than other groups because of their high-quality motorcycles and their use of helmet. As a solution to all the harmful problems caused by the traffic noise, it is necessary for these people to undergo periodical checkups to eliminate late diagnosis of hearing capability loss and problems in the mental and nerve systems. Finally, the municipal management must have special noise management planning in metropolises like Tehran; constructing shopping centers with appropriate and equal costs at each location so that traffics for shopping purposes would decrease; making e-commerce popularized; optimizing public transportation system with adequate capacity.

The authors would like to thank Miss Rafigi, Mr. Norouzi and Mr. Rezaee for the data collection, as well as IA Gazvin University for her financial support throughout the study.

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