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Noise Pollution Chapter 16

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Noise PollutionChapter 16

Source

SPL = 10 log (P2/Po2)

Po = 0.00002 Pa

Units: dB

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

Decibel Addition

For n sources of the same dB:

SPLTotal = 10 log n + SPLo

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.

Point Source

Line Source

- 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

SPL average from a frequency analysis

N = number of measurements taken

Leq

SPL

Time

Time Varying SPL

Who regulates noise levels?

What are some options for abating or controlling traffic noise?

- How effective are they?
- When are they considered?
- When are they installed?
- Of what are they constructed?

1985

1984

Light Pollution