Noise is
defined as unwanted sound. This implies that all noise is sound, and all noise
is subjective. Some sort of noise is inevitable since there cannot be a
noise-free environment. According to Akhionbare (2009), the characteristics of
noise pollution are as follow:
defined as unwanted sound. This implies that all noise is sound, and all noise
is subjective. Some sort of noise is inevitable since there cannot be a
noise-free environment. According to Akhionbare (2009), the characteristics of
noise pollution are as follow:
1.
Wide Range Intensity: The sound intensity to which the human ear is
exposed ranges from 1 billionth (0.000000001) watt to 10 millions watts.
However, sound measurement is usually done in decibels (db) rather than the
watt since the later can be clumsy to work with. In the decibel system,
logarithms of the ratios of loudness are used to compare sound intensities.
Wide Range Intensity: The sound intensity to which the human ear is
exposed ranges from 1 billionth (0.000000001) watt to 10 millions watts.
However, sound measurement is usually done in decibels (db) rather than the
watt since the later can be clumsy to work with. In the decibel system,
logarithms of the ratios of loudness are used to compare sound intensities.
2.
Noise is Basically a City Problem: This is to say that rural areas are relatively
quite compared to the city. This can be explained by the fact of the close
relationship between population density and ambient noise. In general, the
higher the population density, the louder the city.
Noise is Basically a City Problem: This is to say that rural areas are relatively
quite compared to the city. This can be explained by the fact of the close
relationship between population density and ambient noise. In general, the
higher the population density, the louder the city.
3.
Noise has Continued to Increase Over
Time: Sound experts have estimated that ambient city noise in many areas of
the USA has doubled in 20 years. Another investigation estimates that ambient
city noise in Canada increases a half-decibel a year. It can be inferred from
these findings that increase in the level of soundscape over time has to do
with technological progress. (Akhionbare 2009).
Noise has Continued to Increase Over
Time: Sound experts have estimated that ambient city noise in many areas of
the USA has doubled in 20 years. Another investigation estimates that ambient
city noise in Canada increases a half-decibel a year. It can be inferred from
these findings that increase in the level of soundscape over time has to do
with technological progress. (Akhionbare 2009).
4.
Frequency of Sound or Noise: Sound is the quickly varying pressure wave
travelling through a medium. The number of pressure variation per sound is
called the frequency of sound and it’s measured in Hertz (Hz) which is defined
as cycles per second. The higher the frequency, the more high pitched a sound
is perceived. The sound produced by drums has much lower frequencies than those
produced by a whistle.
Frequency of Sound or Noise: Sound is the quickly varying pressure wave
travelling through a medium. The number of pressure variation per sound is
called the frequency of sound and it’s measured in Hertz (Hz) which is defined
as cycles per second. The higher the frequency, the more high pitched a sound
is perceived. The sound produced by drums has much lower frequencies than those
produced by a whistle.
5.
Loudness and the Decibel Scale: another property of noise is it’s loudness. A loud
noise usually has a larger pressure variation and a weak one has smaller
pressure variation.
Loudness and the Decibel Scale: another property of noise is it’s loudness. A loud
noise usually has a larger pressure variation and a weak one has smaller
pressure variation.
Table 1.1: Range of Noise Pollution and their
Measurement
Measurement
|
Source of noise
|
Decibels
|
Characteristics
|
|
Threshold
of hearing |
0
|
Audible
|
|
Normal
breathing |
10
|
Audible
|
|
Leaves
rustling in the breeze |
20
|
Very
quiet |
|
Hospital
ward |
20-80
|
|
|
Whispering
|
30
|
Very
quite |
|
Classroom
|
30-40
|
Quiet
|
|
Library
|
35
|
Quiet
|
|
Quite
restaurant |
50
|
Quite
|
|
Conversation/normal
speech |
60
|
|
|
Window
air conditioner |
60
|
|
|
Commercial
office |
60-65
|
|
|
Car
passing(15 meters away) |
70
|
|
|
Piano
|
80-85
|
|
|
Garbage
disposal unit |
80
|
|
|
Industrial
workshop |
85
|
|
|
Hearing
loss after prolonged |
85
|
|
|
Exposure
|
|
|
|
Vacuum
cleaner |
85
|
|
|
Heavy
city traffic |
90
|
|
|
Heavy
truck(15 meter away) |
90
|
|
|
Food
blender |
93
|
|
|
Gasoline
lawn mower |
96
|
|
|
Farm
tractor |
98
|
|
|
Subway
train |
100
|
|
|
Chain
saw (sawmill) |
110
|
|
|
Unmuffled
motorcycle |
110
|
|
|
Jet
airplane (160 meters overhead) |
120
|
Painful
|
|
Machine
gun at close range |
120
|
Painful
|
|
Jet air craft at take-off (Nunez 2013) 145
|
145
|
Painful
|
(Source: Akhionbare, 2009).
