[ V] Environmental Impacts, Threshold Levels and Health Effects

Transcription

1 [ V] Environmental Impacts, Threshold Levels and Health Effects Noise Part 2 ( ) Mark Brink ETH Zürich D-USYS Homepage: D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 1

2 Topics covered in the previous lecture Overview over Part 2 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 Perceptual organization of sound D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 2

3 Lecture overview for today Physical and subjective description of sound Sound pressure level measurement The measures SPL, L eq, L max, SEL (L E ) 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 D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 3

4 Physical and subjective description of sound D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 4

5 Physical and subjective descriptions of "sound volume" Sound Physical description Subjective description Sound pressure Unit: Pa Sound power Unit: W Sound intensity Unit: Wm -2 Loudness Unit: sone Sound pressure level Unit: db Sound power level Unit: db Sound intensity level Unit: db Loudness level Unit: Phon D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 5

6 Sound pressure level at the ear [db] Dynamic range Auditory sensation area Threshold of pain Musical perception Speech perception 0 db = Pa D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 6

7 Equal loudness curves (German "Kurven gleicher Lautstärke") Hearing threshold D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 7

8 Sound pressure level: common measures D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 8

9 Sound pressure level measurement Sound level meter (SLM) Calculation (sonbase noise map) D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 9

10 SPL in db Most common measures SPL L max L E L eq (Current) Sound pressure level (over time) Maximum level within measurement period (also called SEL ) Sound Exposure Level (Total energy of a defined sound event) Equivalent Continuous Sound Level (energetic average) L E /SEL L max L Aeq Measurement period time D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 10

11 Statistical Measures L 10, L 50, L 90 Note that L 10 > L 50 > L 90 D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 11

12 Attenuation [db] Frequency weighting filters C B A '000 10'000 Frequency [Hz] "db(a)" always means: A-weighted measurement D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 12

13 Time constants (FAST and SLOW) FAST (125 ms) SLOW (1 sec) L AF means: A-weighted, FAST L AS means: A-weighted, SLOW D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 13

14 Demonstrations with sound level meter D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 14

15 Noise exposure D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 15

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 16

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 17

18 Diurnal variation of annual average daily traffic AADT in CH average at 307 automatic traffic counting stations Percent of AADT [%] _ H00 H02 H04 H06 H08 H10 H12 H14 H16 H18 H20 H22 H01 H03 H05 H07 H09 H11 H13 H15 H17 H19 H21 H23 Hour of the day Median 25%-75% Min-Max D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 18

19 Doubling the number of events leads to an increase of 3 db Leq db(a) db Number of vehicles per hour D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 19

20 Range of maximum sound pressure levels L max (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 20

21 Effectiveness of noise abatement measures 0 db 5 db 10 db 15 db Cut traffic by half (3 db) Speed reductions (up to 3dB) Low noise pavement (1-5dB ) 2 m noise barrier (5-10dB ) 4 m noise barrier (10-15dB ) 20 db 25 db 30 db 35 db Encasing/encapsulation ( > 30dB ) 40 db D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 21

22 Sound attenuation outdoors indoors D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 22

23 Sound attenuation outdoors indoors Sound-proof windows db attenuation D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 23

24 Road traffic as noise source Engine vibrations Tires Power train Fan Three types of sources: Air intake and muffler - 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 D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 24

25 Railways as noise source Ripples on rails D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 25

26 Railways as noise source Cast iron brake pad Synthetic brake pads Disk brake D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 26

27 Aircraft as noise source Engines Flaps Landing gear D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 27

28 Noise footprints at landing and take off D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 28

29 Measurement and calculation of noise exposure Brüel&Kjaer 2236 Integrating precision sound level meter CADNA-A calculation of exposure contours on the computer D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 29

30 Calculation of noise exposure Basic principles L W Distance source-receiver L AE Emission Immission Traffic figures, Radar tracks etc.. L Aeq Source Receiver D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 30

31 Measurement of sources with microphone arrays acoustic camera D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 31

32 Measurement of sources with microphone arrays D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 32

33 Sound propagation Influence of wind and temperature gradient cold Day warm warm Night cold D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 33

34 Influencing factors in sound propagation Temperature ± 1 db Throttle pos. ± 1 db Humidity ± 1 db Wind ± 5 db Attenuation Reflections Situational conditions Airport D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 34

35 Most frequently used average measures of noise exposure used in noise legislation in CH (partly), the EU, the US... L eq This is the basic measure: Average level over a certain time period L eq,24 h Average level over 24 hours, h L eq,16h Leq in the period h (Switzerland h) L Night Leq in the period h (Switzerland h) L Evening Leq in the period h L DN (DNL) Day-Night Level: L eq,16h + 0 db L Night + 10 db penalty L DEN (DENL) Day-Evening-Night Level: L 07-19h + 0 db L 19-23h + 5 db penalty L 23-07h + 10 db penalty "Noise metrics" D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 35

36 Most frequently used average measures of noise exposure Formulas for L eq,24 h L DN and L DEN LDay LNight L eq,24 h =10 lg L Day L Night+10 L DN =10 lg L eq,07-19h L eq,19-23h L eq,23-07h+10 L DEN=10 lg D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 36

37 Distribution of noise levels in Switzerland (Year 2010) Road traffic noise Number of people 400' ' '000 L_day L_night L_den L_dn 250' ' ' '000 50' Exposure in db(a) D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 37

38 Distribution of noise levels in Switzerland (Year 2010) Number of people 200' ' '000 Railway noise L_day L_night L_den L_dn 140' ' '000 80'000 60'000 40'000 20' Exposure in db(a) D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 38

39 Noise exposure contours on a map Auckland, NZ N 1-Stunden-Leq von 55 db Auckland, NZ D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 39

40 Road traffic noise map Sursee, Kanton Luzern D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 40

41 Road traffic noise map Brussels, Belgium D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 41

42 sonbase (Swiss noise mapping database) Road traffic noise during day 80 db(a) 0 db(a) D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 42

43 sonbase (Swiss noise mapping database) Rail traffic noise during day 80 db(a) 0 db(a) D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 43

44 sonbase (Swiss noise mapping database) Aircraft noise Euro Airport Basel Zurich Airport Payerne (Air Force) Meiringen (Air Force) Geneva Airport Sion (Air Force) D-USYS M. Brink Environmental Impacts - Noise Part 2 Slide 44