Noise pollution chapter 16
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Noise Pollution Chapter 16. What’s the difference between a sound and a noise? (Intro & Section 16.3). Pressure Waves (Section 16.1). Source. Sound Pressure Level. SPL = 10 log (P 2 /P o 2 ) P o = 0.00002 Pa Units: dB. Typical SPLs.

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Noise Pollution Chapter 16

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Noise pollution chapter 16

Noise PollutionChapter 16


What s the difference between a sound and a noise intro section 16 3

What’s the difference between a sound and a noise?(Intro & Section 16.3)


Pressure waves section 16 1

Pressure Waves (Section 16.1)

Source


Sound pressure level

Sound Pressure Level

SPL = 10 log (P2/Po2)

Po = 0.00002 Pa

Units: dB


Typical spls

Typical SPLs

Measurements by Gordon Hempton, “an acoustic ecologist and sound recordist”


Changes in sound energy

Changes in Sound Energy

Decibel Addition

For n sources of the same dB:

SPLTotal = 10 log n + SPLo


In class activity

In-Class Activity

Your company is purchasing an additional piece of manufacturing equipment. You have two choices. One brand generates 91 dB(A); another brand costs 10% more but generates 88 dB(A). You determine that the current level of noise in the production area is 88 dB(A). The workers are on 8-hour shifts. The OSHA 8-hour noise limit for the area is 93 dB(A). The company has been doing well and has thoughts of expanding production at this location in the near future. Determine which piece of equipment to purchase.


Perception of changes

Perception of Changes


Effect of distance

Effect of Distance

Point Source

Line Source


Effect of distance1

Effect of Distance

  • Point source:  SPL = 20 log (D/Do) 6 dB/DD

  • Line source:  SPL = 10 log (D/Do) 3 dB/DD

  • Hard site: SPL = 10 log (D/Do) 3 dB/DD

  • Soft site: SPL = 15 log (D/Do) 4.5 dB/DD


Calculating spl

Calculating SPL

SPL average from a frequency analysis

N = number of measurements taken


In class activity1

In-Class Activity


Other issues section 16 2

Leq

SPL

Time

Other Issues(Section 16.2)

Time Varying SPL


Weightings

Weightings


Noise abatement and control sections 16 4 and 16 5

Noise Abatement and Control(Sections 16.4 and 16.5)

Who regulates noise levels?


Noise abatement and control

Noise Abatement and Control

What are some options for abating or controlling traffic noise?


Some info about noise barriers

Some Info about Noise Barriers

  • How effective are they?

  • When are they considered?

  • When are they installed?

  • Of what are they constructed?


Metal

Metal

1985

1984


Light pollution

Light Pollution


Earth at night

Earth at Night


Mexico city

Mexico City


Orion rural vs urban sky

Orion: Rural vs. Urban Sky


Solutions

Solutions?


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