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D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 1
[701-0662-00 V]
Environmental Impacts, Threshold Levels and
Health Effects
Lecture 8: Noise - Part 2 (08.04.2020)
Mark Brink
ETH Zürich
D-USYS
Homepage:
http://www.noise.ethz.ch/ei/
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 2
• Overview over Part 2 ("Noise") of the lecture
• Physical basics: Sound pressure and
sound pressure level
• The Decibel scale, Decibel arithmetic
• Perceivable changes of sound pressure level
• Anatomy of the ear
• Principles of auditory perception
• Basilar membrane, hair cells
• Gestalt-principles of auditory perception
Topics covered in the previous lecture
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 3
► Physical and subjective description of sound
► Sound pressure level measurement
► The measures SPL, Leq, Lmax, SEL (LE)
► Frequency weighting filters and Time constants
► Demonstration with Sound Level Meter
► Noise – introduction
► Transportation noise situation in Switzerland
► Noise exposure statistics in the Canton of Zurich
► Time variation of road traffic noise exposure
► Effectiveness of noise abatement measures
► Measurement and calculation of (transportation) noise
► Measurement and calculation of noise exposure
► Sound propagation and attenuation
► Noise maps / noise contours
Lecture overview for today
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 4
Physical and subjective
description of sound
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 5
Physical and subjective descriptions of "sound volume"
Soundpressurelevel – Unit: dB
Soundpowerlevel – Unit: dB
Soundintensitylevel – Unit: dB
Soundpressure
– Unit: Pa
Soundpower
– Unit: W
Soundintensity
– Unit: Wm-2
Physical description Subjective description
Loudness– Unit: sone
Loudness level– Unit: Phon
Sound
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 6
Sound p
ressure
level at th
e e
ar
[dB
]
Dyn
am
ic r
an
ge
0 dB = 0.00002 Pa
Auditory sensation area
Musical perception
Speech perception
Threshold of pain
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 7
Equal loudness curves (German "Kurven gleicher Lautstärke")
Hearing threshold
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 8
Sound pressure level:
common measures
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 9
Sound pressure level measurement
Sound level meter (SLM) Calculation (sonBASE noise map)
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 10
Most common measures
SPL (Current) Sound pressure level (over time)
Lmax Maximum level within measurement period
LE (also called „SEL“) Sound Exposure Level (Total energy of
a defined sound event)
Leq Equivalent Continuous Sound Level (energetic average)
time
SP
L in d
B
Measurement period
LE/SEL
Lmax
LAeq
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 11
Statistical Measures L10, L50, L90
Note that L10 > L50 > L90
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 12
Frequency weighting filters
Att
en
uati
on
[d
B]
Frequency [Hz]
+20
+0
-20
-40
-60
10 100 1'000 10'000
A
B
C
→ "dB(A)" always means: A-weighted measurement
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 13
Time constants (FAST and SLOW)
→ LAF means: A-weighted, FAST
→ LAS means: A-weighted, SLOW
FAST (125 ms)
SLOW (1 sec)
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 14
Demonstrations with sound level meter
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 15
Noise exposure
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 16
... lets start with road traffic noise
Road traffic is the single most
dominant noise source worldwide!
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 17
Course of 1h-Leq of road traffic noise over a week
1h-Leq
Vehicles per hour
% trucks
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 18
Diurnal variation of annual average daily traffic AADT in CH
H00
H01
H02
H03
H04
H05
H06
H07
H08
H09
H10
H11
H12
H13
H14
H15
H16
H17
H18
H19
H20
H21
H22
H23
Hour of the day
_
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Pe
rce
nt
of
AA
DT
[%
]
Median
25%-75%
Min-Max
average at 307 automatic traffic counting stations
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 19
Number of vehicles per hour
LeqdB(A)
25 50 75 100 125 150 175 200 225 250
30
35
40
45
50
55
60
65
70
1
3 dB
Doubling the number of events leads to an increase of 3 dB
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 20
Range of maximum sound pressure levels Lmax
(at a distance of 7.5 m)
Car
Pickup/Van
Bus
Light truck
Heavy truck
Motorbike
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 21
0 dB
35 dB
40 dB
15 dB
5 dB
25 dB
30 dB
20 dB
10 dB
Encasing/encapsulation ( > 30dB )
4 m noise barrier (10 - 15dB )
2 m noise barrier (5 - 10dB )
Low noise pavement (1 - 5dB )
Cut traffic by half (3 dB)Speed reductions (up to 3dB)
Effectiveness of noise abatement measures
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 22
Sound attenuation outdoors – indoors
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 23
Sound attenuation outdoors – indoors
Sound-proof windows
30-40 dB attenuation
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 24
TiresEngine vibrations
Fan
Air intake and muffler
Power train
Three types of sources:
- Engine and transmission noise: dominant during acceleration, in low gears
- Tire/road noise: dominates on community roads and highways
- Aerodynamic noise: only at high speeds
Road traffic as noise source
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 25
Ripples on rails
Railways as noise source
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 26
Railways as noise source
Cast iron brake pad Synthetic brake pads Disk brake
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 27
Flaps
Landing gear
Engines
Aircraft as noise source
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 28
Noise footprints at landing and take off
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 29
Brüel&Kjaer 2236 Integrating
precision sound level meterCADNA-A calculation of exposure
contours on the computer
Measurement and calculation of noise exposure
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 30
LW Distance source-receiver
LAE
ReceiverSource
Traffic figures,
Radar tracks etc..
LAeq
Calculation of noise exposureBasic principles
Emission Immission
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 31
Measurement of sources with microphone arrays
acoustic camera
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 32
Measurement of sources with microphone arrays
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 33
Influence of wind and temperature gradient
cold
warm
warm
cold
Day
Night
Sound propagation
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 34
Airport
Temperature ± 1 dB
Wind ± 5 dBHumidity ± 1 dB
Throttle pos. ± 1 dB
Attenuation
ReflectionsSituational conditions
Influencing factors in sound propagation
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 35
• Leq This is the basic measure: Average level over a certain time period
• Leq,24 h Average level over 24 hours, 00-24 h
• LDay Leq in the period 07-23 h (Switzerland 06-22 h)
• LNight Leq in the period 23-07 h (Switzerland 22-06 h)
Most frequently used average measures of noise exposureused in noise legislation in CH (partly), the EU, the US...
• LDN (DNL) Day-Night Level:
L07-22h + 0 dB
L22-07h + 10 dB penalty
• LDEN (DENL) Day-Evening-Night Level:
L07-19h + 0 dB
L19-23h + 5 dB penalty
L23-07h + 10 dB penalty
"Noise metrics"
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 36
Most frequently used average measures of noise exposureFormulas for Leq,24 h , LDN , and LDEN
( ) ( )
07-22h 22-07h0.1 Leq +0 0.1 Leq +10
DN
15 9L =10 lg 10 + 10
24 24
( ) ( ) ( )
eq,07-19h eq,19-23h eq,23-07h0.1 L +0 0.1 L +5 0.1 L +10
DEN
12 4 8L =10 lg 10 + 10 + ×10
24 24 24
( ) ( )Day Night0.1 L 0.1 L
eq,24 h
16 8L =10 lg 10 + 10
24 24
used in USA
used in EU
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 37
0
50'000
100'000
150'000
200'000
250'000
300'000
350'000
400'000
40 45 50 55 60 65 70 75 80
Number of people
Exposure in dB(A)
L_day
L_night
L_den
L_dn
Distribution of noise levels in Switzerland
(Year 2010)Road traffic noise
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 38
Distribution of noise levels in Switzerland
(Year 2010)Railway noise
0
20'000
40'000
60'000
80'000
100'000
120'000
140'000
160'000
180'000
200'000
40 45 50 55 60 65 70 75 80
Number of people
Exposure in dB(A)
L_day
L_night
L_den
L_dn
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 39
1-Stunden-Leq von 55 dBN
Noise exposure contours on a mapAuckland, NZ
Auckland, NZ
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 40
Road traffic noise mapSursee, Kanton Luzern
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 41
Road traffic noise mapBrussels, Belgium
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 42
Road traffic noise during day
sonBASE (Swiss noise mapping database)
80 dB(A)
0 dB(A)
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 43
Rail traffic noise during day
sonBASE (Swiss noise mapping database)
80 dB(A)
0 dB(A)
D-USYS • M. Brink • Environmental Impacts - Noise Part 2 Slide 44
Aircraft noise
sonBASE (Swiss noise mapping database)
Zurich Airport
Euro Airport Basel
Geneva Airport
Payerne (Air Force)
Sion (Air Force)
Meiringen (Air Force)
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