1 Terseer Terrumun Humbe
2 Samuel Terhemba Kungur
Department of Physics
College of Education Katsina-Ala
This research presents the results obtained from environmental noise measurements at selected locations in Makurdi metropolis. Twenty-nine (29) locations throughout Makurdi were selected to establish background noise levels and dominant noise sources at these sites. These locations were selected because of different sources of intrusive noise, traffic volumes and commercial activities. A precision grade sound level meter was used to measure sound intensity noise levels around sources. Passenger-loading parks had the highest noise level of 130dBA exceeding the WHO recommended limit of 70dBA while noise levels at residential areas were found to be acceptable. The result of this study shows that the major source of noise in Makurdi metropolis can be attributed to traffic noise. Based on the recommendations of the World Health Organization (WHO), only 10 locations out of 29 are under normally acceptable situations while the noise levels of other areas were not acceptable. Among the recommendations proffered to curb the present noisy state of the city is the fact that drawing a noise map for the city will identify noise spots and sources thus creating the climate necessary for the implementation of noise-reduction programs.
Noise pollution is a significant environmental problem in many urban areas. This problem has not been properly recognized despite the fact that it is steadily growing in developing countries. Davis & Masten (2004) stated three valid reasons as to why widespread recognition of noise pollution problem has not materialized in a similar fashion as have air and water pollution problems. These reasons are summarized in the definition and perception of noise as a subjective experience, short decay time, and difficulty to associate cause with effect when it comes to health impacts.
Noise pollution is recognized as a major problem for the quality of life in urban areas all over the world. As a result of the increase in the number of cars and industrialization, noise pollution has also increased. Noise in cities has reached disturbing levels. Residences far from noise sources and near silent secondary roads are currently very popular. People prefer to live in places far from noisy urban areas (Ozer, Yilmaz, Yesil and Yesil, 2009).
In contrast to many other environmental problems, noise pollution continues to grow and is accompanied by an increasing number of complaints from people exposed to the noise. The growth of noise pollution has unhealthy effects. It also adversely affects future generations, and has socio-cultural, aesthetic and economic effects (Yilmaz and Ozer, 2005). The most important factors raising noise pollution in urban areas include inter alia, vehicular traffic, neighborhood, electrical appliance, TV and music systems, public address systems, railway and air traffic, and generating sets. Even we fall prey to the noise generated by the household equipment used by us (Singh and Daver, 2004).
Many surveys addressing the problem of noise pollution in many cities throughout the world have been conducted, and have shown the scale of discomfort that noise causes in people’s lives. Existing evidence indicating that noise pollution may have negative impacts on human health has justified research in order to provide better understanding of noise pollution problems and control (Singh and Daver, 2004).
Depending on this duration and volume, the effects of noise on human health and comfort are divided into four categories: physical effects, such as hearing defects; physiological effects, such as increased blood pressure; irregularity of hearth rhythms and ulcers; psychological effects, such as disorders, sleeplessness and going to sleep late, irritability and stress; and finally effects on work performance, such as reduction of productivity and misunderstanding what is heard (Quis, 2001).
City noise levels can be investigated in three different ways as traffic and transportation; industrial activities; sport, marketing and entertainment facilities (Dursun et al., 2006). In comparison to other pollutants, the control of environmental noise has been hampered by insufficient knowledge of its effects on humans and lack of defined criteria.
In Nigeria, the problem of noise pollution is widespread. Several studies report that noise levels in metropolitan cities exceed specified standard limits. Anomoharan, Iwegbue, Ogbeierhoro, and Egbai (2008) conducted a study in Abraka, Nigeria and found the peak noise level at Abraka road junction to be 100dB(A). This noise level is higher than the recommended level of 60dB(A) for commercial and residential areas. Ighoroje et al (2004) investigated the level of noise pollution in selected industrial locations in Benin City. The average ambient noise levels in Sawmills and food processing areas was above 90dB(A). This noise level is well above the healthy noise level of 60dB(A).
Noise pollution is not a unique problem for developing countries like Nigeria only. Many researchers have revealed that, more than 130 million people in Europe suffer from exposure to noise levels above 65dB(A) (CEC, 2000). Bond (1996) reports that 16% of people in Europe are exposed to 40dB(A) or more of traffic noise in their bedrooms at night compared with WHO’s average estimates of 30 to 35dB(A) for undisrupted sleep. The environmental noise level of 70dB(A) was recommended by WHO for industrial, commercial, shopping and traffic areas, indoors and outdoors to prevent impairments.
Table 1.0: WHO Guideline for Community Noise (Dursun, Ozedimir, Karabork & Kocak, 2006)
|Environment||Critical Health Effect||Sound level dB(A)|
|Outdoor living areas||Annoyance||50 – 55|
|Indoor dwellings||Speech intelligibility||35|
|School classrooms||Disturbance of communication||35|
|Industrial, commercial and traffic areas||Hearing impairment||70|
|Music through ear phones||Hearing impairment||85|
|Ceremonies and entertainment||Hearing impartment||100|
In Nigeria, there is no legal framework upon which noise pollution can be abated. Federal Environmental Protection Agency (FEPA) in Nigeria only provided daily noise exposure limits for workers in industry (i.e. 90dB(A)). In short, the Nigerian government and her citizenry appear not to be conscious of the present and future impact of noise-induced health hazards in their environment. Unless and until measures are taken to control the level of noise, the ongoing urbanization as industrialization may complicate the problem so much that it becomes incurable.
The ability to measure ambient noise levels and represent them on a map should provide a powerful tool for identifying noise sources, its spread, its impact and make decisions relating to its control and management. An ideal noise pollution map can give basic information about city traffic plan, its development, investigation of noise removal research and noise polluted areas that must be worked on furthermore, noise maps are the evaluation of environmental study on different noise sources (highway, airport, railway and industrial noise) and investigation of basic human problems (Leth, 2003).
Materials and Method
This research is based on the results of outdoor sound level measurements carried out in October, 2013 at 29 different locations (5 commercial centers, 6 road junctions and busy roads, 5 passenger-loading parks and 13 low density areas) in Makurdi metropolis, the capital city of Benue State. Table 2 shows the locations selected for the noise level measurements in Makurdi metropolis.
Table 2: Locations selected for noise level measurements in Makurdi metropolis
|5.||Benue Links Park|
|6.||Pleasure Travels Park|
|7.||London Line Motor Park|
|8.||New Nyanya Mass Transit Park|
|12.||Mr. Biggs Roundabout|
|18.||Old Assembly Quarters|
|26.||Iyorchia Ayu Road|
|27.||Old Otukpo Road|
The main equipment for field measurement was the precision grade sound level meter. This meter is designed to provide the user a quick, reliable and easy way to measure sound intensity level around sources.
The measurements were done at street level (i.e at road functions, passenger-loading parks and residential areas). The instrument was held comfortably in hand with the microphone pointed at the suspected noise at a distance not less than 1m away and the sound pressure level (L) measurements were recorded. This procedure was carried out for morning, afternoon, evening and night values since activities vary at different times of the day.
From these readings, commonly used community noise assessment quantities sound pressure level,, the daytime average sound level, , the day and night time average sound level, , the noise pollution level, LNP as well as the traffic noise index, TNI were computed.
Accordingly, the sound intensity level L of a sound wave is defined in the equation.
Where is the reference intensity; taken as which corresponds roughly to the lowest sound that can be perceived by the human ear. Intensity levels are expressed in decibels; abbreviated dB(A).
Results and Discussion
Noise measurements were done when the effects on the noise sources of variable factors (e.g. wind spread and rainfall) were at minimum i.e. under suitable meteorological conditions and the average noise descriptive were determined per location. Each measurement value of noise intensity was obtained by computing the mean of 5 readings per location. Table 3 shows that daily average values of noise descriptors for all the sites surveyed. The sites are designated with numbers 1 – 29
Table 3: Average noise descriptors at various study locations
From table 3, location 6 has the highest values of (89dBA), (91dBA), (75dBA), TNI(130dBA), (103dBA), (90dBA), (86dBA), (95dBA).
Location 10 has the second highest values of (82dBA), (87dBA), (70dBA), TNI(115dBA), (100dBA), (85dBA), (81dBA), (90dBA). These locations are passenger loading parks and busy road junctions respectively. The background noise levels () at these locations are highest in all the sites surveyed. This is due to intrusive noise sources from human conversation, due to commercial activities, radio players and electric generators.
The lowest noise descriptor values were recorded at locations 16 and 13 with values (44dBA), (46dBA), (42dBA), TNI(32dBA), (50dBA), (42dBA), (56dBA), (61dBA) and (45dBA), (42dBA), (35dBA), TNI(46dBA), (58dBA), (48dBA), (43dBA), (50dBA) respectively. These locations are low density residential areas. Among the factors responsible for differences in noise levels in the sites surveyed include location sites presence of intrusive noise, traffic volume and commercial activities.
High noise level exposure in the city occurs mostly in the daytime at passenger-loading parks and road junctions. This is followed by commercial centers and major roads. In these locations, apart from traffic noise, other intrusive noise sources include noise from record players, loudspeakers, hawking and human conversation.
In many countries, the efforts to check the alarming increase in environmental noise pollution have adopted permissible noise standards. The World Health Organization (WHO) as shown in Table 1.0 has suggested a standard guideline value for average outdoor noise levels of 55dB(A) in order to prevent significant interference with the normal activities of local communities. Table 1.0 shows the WHO guideline values for community noise levels listing also the critical health effects ranging from annoyance to hearing impairment.
The result of this study shows that noise levels () in all passenger-loading parks surveyed (71 – 91dB(A)) are higher than the recommended values by WHO (i.e. 70dB(A)). In other locations, such as residential areas, the measured noise values () can be classified as acceptable.
In this study, a select assessment of environmental noise levels of Makurdi metropolis was carried out. Twenty-nine (29) selected sites were surveyed for noise pollution levels. The result of this study shows that at locations near passenger-loading parks and road junctions, the equivalent noise level, background noise level and peak noise level were higher compared to sites monitored near low density residential areas.
This investigation revealed that noise levels at 19 of 29 measurement points exceeded the recommended limit of 60dB(A) by value of 3 – 31dB(A). Hence, the present status of noise pollution in Makurdi metropolis may pose health risk to the residents.
The sources of noise pollution identified in this study and its effect on the public in Makurdi is significantly similar throughout many Nigerian cities. The challenges posed by noise pollution to human health and the environment have not yet received the attention they deserve. Though policies regulating noise pollution in Nigeria as well as the world have lofty aims, there is however the need for proper implementation.
This study revealed high noise levels in Makurdi metropolis. A number of remedies can be taken to reduce the environmental (traffic) noise pollution in the city. The possible control measures to abate noise pollution in Makurdi metropolis and in Nigerian urban cities are given below:
- Provision of noise maps to show the spatial distribution of noise levels in the city. A noise map is a tool that gives a comprehensive look at the problem of multiple sources and receivers thus creating noise abatement plans for noisy areas.
- Provision of smooth roads and good road maintenance. Well-maintained, smooth-surfaced roads are less noisy than those with cracked, damaged and patched surfaces. The physical characteristics of the road surface and its surroundings play a large role in determining noise output.
- Public awakening and education. The masses are still ignorant of the grave effects of noise pollution. In this regard television, radio, internet and newspapers should give this campaign a wide publicity since this could have the effect of creating the climate necessary for implementation of a noise-reduction program.
Anomoharan, O; Iwegbue, C. M. A; Ogbeierhoro, I. O; & Egbai, I. J. C. (2008). Investigation of environmental noise pollution level of Abraka, in Delta state, Nigeria. Trends in Applied Sciences Research, 3, 292-297.
Bond, M. (1996) Plague by noise. New Scientist 16, 14-15.
Commission of the European Communities (2000). Directive of the European parliament and of the council relating to the assessment and management of environmental noise. COM468 Final.
Davis, M. L; & Masten, S. J. (2004). Principle of environmental engineering and science. McGraw-Hill International.
Dursun, S; Ozdemir, C; Karabork, H; & Kocak; S. (2006). Noise pollution and map of Konya City in Turkey. J. Int. Environmental Application and Science, 1, 63-72.
Igboroje, P. D. A; Marchie, C; Nwobodo, E. D. (2004). Noise induced hearing impairment as an occupational risk factor among Nigerian traders. Nigerian Journal of Physiological Sciences, 9, 14-19.
Ozer, S; Yilmaz, H; Yesil, M; Yesil, P; (2009) Evaluation of noise pollution caused by vehicles in the city of Tokat, Turkey. Scientific Research and Essay, 4, 1205-1212.
Quis, D; (2001) Annoyance from road traffic noise: A Review. J. Environ Psychol., 21, 101-120.
Singh, N; & Daver, S. C; (2004). Noise pollution sources, effects and control. Journal of Human Ecology, 16, 181-187.
Yilmaz, H; & Ozer, S. (2005). Evaluation and analyzing of environmental noise pollution in the city of Erzurum, Turkey. Int. J. Environ Pollut., 23, 438-448.