Noise Metric overview

Aircra&NoiseMetrics
Aircra&Noise
isthe
NewSecondHandSmoke
Aircra&NoiseMetrics
Ifyourmeasurementsare
Inadequate,
Youdon’thaveto
Takeresponsibility
Fordoinganythingabout
Whatyouhaven’tmeasured
Whereweareandhowwegothere
•  TheNoiseControlActof1972empoweredtheEPA
todeterminenoiselimitstoprotectthepublichealth
andwelfare,andtoestablishanoisecontroloffice.
•  1973EPAestablishedcommunitynoiselevelsforaircra&,
usingA-weighteddecibelmeasures.
•  AtthatQmeEPAacknowledgedthemeasureswere
inadequate,butconvenientforpublicrelaQons.
WhatEPADecidedin1973
–  “Toperformsuchanalysis,especiallyforQmevarying
sounds,requiresaverycomplexsetofequipment.A
frequency-weightedsoundpressurelevel,onthe
otherhand,isaone-numbermeasureofnoisethat
canbeobtainedwithsimpleequipment….Although
thisapproachisnotsa'sfactoryfordetailedanalysis
forengineeringnoisecontrol,itprovidesa
saQsfactorydescripQonofnoisefromaresponse
viewpointwithintheaccuracyreasonablefor
communitynoise-evaluaQons.”p.3
– 
– 
ImpactCharacterizaQonofNoiseIncludingImplicaQonsofIdenQfyingandAchievingLevelsofCumulaQveNoise
Exposure;EPAAircra&/AirportNoiseStudy27July1973
h\p://nepis.epa.gov/Exe/ZyPDF.cgi/9101DPQN.PDF?Dockey=9101DPQN.PDF
WhatEPADecidedin1973
•  “OnedifficultyintheuseoftheA-…weighted
soundlevelisthatpsychoacousQcjudgment
dataindicatethateffectsoftonalcomponents
aresomeQmesnotadequatelyaccountedfor
byasimplesoundlevel.”p.4
ImpactCharacterizaQonofNoiseIncludingImplicaQonsofIdenQfyingandAchievingLevelsofCumulaQve
NoiseExposure;EPAAircra&/AirportNoiseStudy27July1973
–  h\p://nepis.epa.gov/Exe/ZyPDF.cgi/9101DPQN.PDF?Dockey=9101DPQN.PDF
– 
WhatEPADecidedin1973
•  “AnoutdoorLdnofapproximately60dBorlessis
requiredinorderthatnomorethan23%ofthe
populaQonexposedtonoisewouldbeindividually
highlyannoyed….Itthereforeappearsreasonableto
proposeanLdnof55to60dBasthelongrangegoal
formaximumpermissableaveragesoundlevelwith
respecttohealthandwelfare.(Notethatthislevelis
notconsideredopQmum,merelytheupperlimitof
permissibility.Noendorsementisintendedof
degradaQonofexisQngareashavingalowernoise
level.)”p.43
– 
– 
ImpactCharacterizaQonofNoiseIncludingImplicaQonsofIdenQfyingandAchievingLevelsofCumulaQveNoiseExposure;EPA
Aircra&/AirportNoiseStudy27July1973
h\p://nepis.epa.gov/Exe/ZyPDF.cgi/9101DPQN.PDF?Dockey=9101DPQN.PDF
OSHADefiniQons
•  AverageLevel:“Theaveragedoesnotincludeany
soundbelowthethreshold.”!!!
–  Example:thresholdsetto80dB,andexchangeor
doublingrateis5dB.In1-hournoisemeasurementin
officewhereA-weightedsoundlevelwas50-70dB.If
thesoundneverexceeded70,therewouldbeno
reading.Ifthesoundwereexceededforafew
secondsduetoatelephoneringing,ONLYthose
soundswouldcontributetotheaverage,resulQngina
levelofapproximately40dB,notablylowerthanthe
actuallevelsintheenvironment.
–  LDNDay-nightlevel24-houraverage
EPAOfficeofScienQficAssistanttoDAA/NoiseReport
#EPA550/9-79-100ProtecQveNoiseLevels
EPAOfficeofScienQficAssistanttoDAA/NoiseReport
#EPA550/9-79-100ProtecQveNoiseLevels
WhatEPADecidedin1973
•  “Thedisturbancebyindividualnoiseevents
andoccasionalhighnoiselevelsshouldbe
controlledbymaximumpermissiblenoise
levelsforindividualeventsestablishedby
localauthoriQes.Controloversuchevents
shouldnotbea\emptedbyloweringthe
averagesoundlevel.”p.44
ImpactCharacterizaQonofNoiseIncludingImplicaQonsofIdenQfyingandAchievingLevelsofCumulaQve
NoiseExposure;EPAAircra&/AirportNoiseStudy27July1973
–  h\p://nepis.epa.gov/Exe/ZyPDF.cgi/9101DPQN.PDF?Dockey=9101DPQN.PDF
– 
WhatEPADecidedin1973
•  “Insummary,itisarealisQcgoaltokeeptheday/
nightaveragesoundlevelbelow60dBinresidenQal
areas,wheretheaverageincludesa10decibel
penaltyonnighrmenoiselevels.InconjuncQon
withnoiseemissionstandardsandlocalcontrolof
individualnoiseevents,suchalimitisexpectedto
insure,accordingtopresentknowledge,anoise
environmentwithoutsignificanteffectonpublic
healthandwelfare.”p.44
ImpactCharacterizaQonofNoiseIncludingImplicaQonsofIdenQfyingandAchievingLevelsofCumulaQve
NoiseExposure;EPAAircra&/AirportNoiseStudy27July1973
–  h\p://nepis.epa.gov/Exe/ZyPDF.cgi/9101DPQN.PDF?Dockey=9101DPQN.PDF
– 
WhatEPADecidedin1973
•  “Anoisemeasuremustbefoundthatcollapsesthe
arrayofstaQsQcalparametersdescribedaboveintoa
singleuseablefigurefordescribingthenoise
exposureofaneighborhood,evenifthat
simplificaQonentailssomecompromisewiththe
currentstandardofhighesta8ainableaccuracy.”
AppendixA,“Jus$fica$onoftheuseoftheaverage
soundlevelasameasureofcommunitynoise”p.A-3
ImpactCharacterizaQonofNoiseIncludingImplicaQonsofIdenQfyingandAchievingLevelsofCumulaQve
NoiseExposure;EPAAircra&/AirportNoiseStudy27July1973
–  h\p://nepis.epa.gov/Exe/ZyPDF.cgi/9101DPQN.PDF?Dockey=9101DPQN.PDF
– 
WhatEPADecidedin1973
•  “TheindicaQonsthata‘D-weighQng’mightulQmatelybemore
suitableforevaluaQngtheintegratedeffectsofnoiseonman,than
theA-weighQng,however,suggeststhatatsuchQmeasa‘DweighQng’becomesstandardizedandavailableincommercial
instrumentaQon,itsvalueastheweighQngforenvironmentalnoise
shouldbeconsidered,todetermineifachangefromtheAweighQngiswarranted.”p.5
–  Note:D-weighQnghasbeenfoundnottobeasaccurateindescribing
aircra&overflightnoiseasisC-weighQng.SeeWHOCommunityNoise
Report2000,Wylereport2001andPartnershipforAirTransportaQon
NoiseandEmissionsReducQonFAA/NASA/TransportCanada2007
– 
– 
ImpactCharacterizaQonofNoiseIncludingImplicaQonsofIdenQfyingandAchievingLevelsofCumulaQveNoise
Exposure;EPAAircra&/AirportNoiseStudy27July1973
h\p://nepis.epa.gov/Exe/ZyPDF.cgi/9101DPQN.PDF?Dockey=9101DPQN.PDF
A&er1973
•  In1982fundingforfurtherresearchand
enforcementwasdisconQnued
•  Statesandlocalgovernmentsdonotestablish
theirownstandardsbecausethe1973lawis
sQllthelawoftheland,althoughthe1973
reportonAircra&noiseindicatesthatlocal
governmentscansetlocalnoisestandards.
DecibelsforNon-acousQcians:
It’sComplicated
•  Theterminologyistechnicalandnotused
consistentlyacrossmeasurementsituaQons
•  Themathgetscomplexveryquickly
•  EPAandFAAcountonmostpeoplenotbeing
abletoslogthroughthemath,the
terminology,andthemeasurementissues
•  WeWILLneedexpertstoguideus
TheBasics
•  Theearperceivesdifferentpitchfrequencies
(Hertz)atdifferentlevels.Weperceivehigher
frequenciesmoreeasilythanlowerfrequencies
BUT….
•  Lowfrequenciescanbe“felt”morethanheard,
throughboneconducQon(Think“Jaws”movie
theme—anorienQngresponse--andhowyour
bodyvibrateswhenthebassisturnedup)
•  Airplanesgeneratesoundsacrossawiderangeof
frequencies,mostofwhichtheFAAdoesnot
measureforcommunitynoisepurposes
Whatgetsmeasured
•  Decibelmetersarenotexactlythesamething
assoundspectrumanalyzers.
•  Decibelmetersmeasuresoundpressure
•  Decibelmetersuse“weighQng”tofilterout
somepartsofthesoundspectrum
•  ThisallowsagenciesliketheFAAto“fudge”
theirnumbers.
Whataboutmyexperienceofnoise?
•  ThepsychologistJohnG.Neuhofffoundout
thatfortherisinglevelourhearingismore
sensiQvethanforthedeclininglevel.Forthe
samesoundleveldifferencethechangeof
loudnessfromquiettoloudisstrongerthan
fromloudtoquiet.
• 
JohnG.Neuhoff,"Anadap'vebiasinthepercep'onofloomingauditorymo'on",2001,Ecological
Psychology13(2)pp.87-110and
JohnG.Neuhoff,"PerceptualBiasforRisingTones",1998,Nature,Volume395,10September • 
h\p://www.sengpielaudio.com/TableOfSoundPressureLevels.htm
• 
Howmanydecibelsdoesittaketo
doublethepercepQonofnoise?
• 
• 
• 
• 
• 
• 
• 
Thereisaconstantuncertaintyoftheanswertotheques'on:"Howmanydecibels(dB)are
doublingasound"?or"Whatistwicethesound?"
Answer:Doublingmeansthe"factor2".Whatdoesdoublingofa"sound"mean?
Doublingthe(sound)intensityisobtainedbyanincreaseofthesoundintensitylevel(power)of3
dB.
Doublingthesoundpressureisobtainedbyanincreaseofthesoundpressurelevel(voltage)of6
dB
Doublingtheloudnessfeelingisobtainedbyanincreaseoftheloudnesslevel(psychoacousQc)of
about10dB.
Simpleruleofthumb:Whenworkingwithpower,3dBmeansdouble(twice)thefactorand10dB
means10-fold.Whenworkingwithvoltageorcurrent,6dBmeansdouble(twice)thefactorand20
dBmeans10-fold.
h\p://www.sengpielaudio.com/TableOfSoundPressureLevels.htm
WhatisLowFrequencyNoise?
•  LowFrequencyNoise(LFN)isnoisebelowthe
FAAmeasuredpitchfrequencyof500Hz
(abouttheBabovemiddleConapiano)
•  Itisgeneratedbytheexhaustofjetenginesat
about20-200Hz(approximatelyG#below
middleCtothebo\omofthepianorange)
BiophysicspercepQbility
Low frequencies audible for
everyone: beat, difference tone ● 
a. mono 220 Hz
b. mono 222 Hz
Superposition of nearly equal,
audible, tones (a and b)
c. mono 220 + 222 Hz
↑
this amplitude modulation can
be acoustic (c) and neural (d)
(Useful application: tuning
musical instrument)
d. stereo: left 220, right 222
(Click here, in presenting (Source: M. Oud 2012)
mode of powerpoint.
Use head phone.)
DrMireilleOud,Congress“Sound,VibraQons,Airquality,Field&Building”,6November2012,Nieuwegein,The
10Netherlands
of
LowFrequencyNoiseStudy
PartnershipforAiRTransportaQonNoise&EmissionsReducQon
FAA/NASA/TransportCanada
Hodgdon,Atchley,Bernhard
April,2007
•  Reasonsforfocusingonthelow-frequencycomponentsof
aircra&noisearethat
•  1)low-frequencysoundencounterslessabsorpQonasit
travelsthroughtheairthanhigherfrequencysound,soit
persistsforlongerdistancesfromtheairport,
•  2)theamountofsoundtransmi\edfromtheoutsideto
theinsideofbuildingsisgreateratlowfrequenciessound
thanathigherfrequencies,
•  4)standardnoisemodelsusedforassessingairportnoise
neglectsourcenoisebelow50Hz,3and
•  5)priorresearchindicatesthatfrequenciesinthe20–80
HzrangehaveaninfluenceonthepercepQonoflowfrequencynoise.1,4,5
LowFrequencyNoiseStudy
PartnershipforAiRTransportaQonNoise&EmissionsReducQon
FAA/NASA/TransportCanada
Hodgdon,Atchley,Bernhard
person detects the noise and at which
that noise is perceived as being oppressive. This illustrates
narrowing of dynamic range mentioned previously.
April,2007
Figure 2. Two different versions of Tokita and Nakamura's threshold for the perception of low-frequency
noise. The left-hand plot is for direct exposure. The right-hand plot is for nominal levels of
outdoor sound that would elicit a particular response from occupants inside a house.
Figures 3 and 4 illustrate the utility of the criteria curves or thresholds in assessing the
potential for annoyance due to low-frequency noise. Figure 3 shows the results of a parabolicequation model of sound propagation in the vicinity of Schiphol from Ref. 4. The colors
represent values of sound pressure levels. The figure on the left is a no-wind condition, the one
on the right a wind blowing from the northeast. One of the test houses at Schiphol was located
approximately 2 km to the southwest of the runway. Comparing the two figures, the northeast
wind results in an increased sound level at the location of the house. The reason for this is that
LowFrequencyNoiseStudy
PartnershipforAiRTransportaQonNoise&EmissionsReducQon
FAA/NASA/TransportCanada
Hodgdon,Atchley,Bernhard
April,2007
• 
• 
• 
• 
AssessmentofTokita&NakamuraThresholdforpredic'ngpercep'onofLFN:
Finding:TheTokita&Nakamuraannoyancethresholdswerevalidatedas
predictorsofannoyanceduetolow-frequencyaircra&noise.Theywerefoundto
relatefavorablytothesubjecQveannoyanceassessments.Linearregression
analysisshowedthattheC-weightedsoundexposurelevelLCEwasthebestsinglemetricpredictorofsubjecQveannoyanceresponse,explainingover90%ofthe
variabilityofthedataset.LCEcorrelatedbe\erwiththesubjecQvedatathan
metricsspecificallydesignedtoquanQfylow-frequencynoiseimpact.
Recommenda'on:TheTokita&Nakamurathresholdsshouldbeusedasindicators
ofthepotenQalforannoyanceduetolow-frequencyaircra&noise.LCEshouldbe
usedasasingle-numbermetricforassessingthepotenQalforannoyancewhen
highlevelsoflow-frequencyaircra&noisearepresent.
Overall,thefindingssuggestthatpeoplearerespondingtothebroad
spectralcontentandanypredicQvemetricshouldquanQfy
thefullbroadbandnoise.Loudnessalgorithmsshouldinclude
frequencycontentbelow50HztoopQmallycorrelatewith
thepercepQonoflowfrequencynoise.
WyleAcousQcsGrouptoSFONAO
2001
•  SoundlevelmeasurementsusingA-weighQng
de-emphasizefrequenciesbelow500Hz
•  NoisegeneratedbydeparQngaircra&contains
mostofitssoundspectrumbelow200Hz
•  Atthesefrequencies,noisepropagatesover
longdistances[and],travelsquitefreely
throughstructures
cation of these two weightings to the backblast spectrum of Figu
resented in Figure 2-3, showing that C-weighting represen
ovement
over A-weighting in properly accounting for the low-freq
Sharp,Gurovich,&Albee,WyleAcousQcsGroup,
e component of the noise.
forNoiseAbatementOffice,SFO,2001
20
Relative Sound Pressure Level, dB
C-Weighting
0
-20
-40
A-Weighting
-60
-80
8
16
31.5
63
125
250
500
1/3-Octave Band Center Frequency, Hz
1000
2000
4000
A-weighQng,ahighpassfilter
h\p://clas.mq.edu.au/speech/acousQcs/frequency/spectral.html
Highpassfilter."HP"indicatesthehighpassfrequency.Thisfilterpassesspectral
componentsabovethisfrequencyandblocksspectralcomponentsbelowthis
frequency.
that the noise level changes quite rapidly with angle in the region of the rear
lobes, particularly in the case of the LBPR engine, and that there is a
significant quiet zone directly behind the engine. This means that the noise
Sharp,Gurovich,&Albee,WyleAcousQcsGroup,forNoiseAbatementOffice,SFO,2001
levels to the rear of a LBPR engine will be dependent on engine orientation,
both horizontally (side to side) as the aircraft moves down the runway, and
vertically (up and down) as it climbs. The result is that the noise level at a
distant observation point to the rear and side of the runway will vary with
aircraft position along the runway as the angle to the aircraft changes. The
horizontal variation will be greatest for observers close to, and to the side
of, the runway, and will diminish as the observation distance from the
runway increases. This effect will be less evident for a HBPR engine where
the rear lobe is less pronounced.
FAAdoesnotmeasurenoisegeneratedin
theRedpa\ern
The characteristics of the directivity pattern of a LBPR jet engine at low (160
Hz) and high (1000 Hz) frequencies are given in Figure 2-6 for a DC-9 with
a hushkitted JT8D-7 engine2, showing that the majority of the noise radiated
to the rear of the aircraft is concentrated at low-frequencies.
100 Hz
1000 Hz
Figure 2-6. Directivity Patterns for a JT8D Engine at 100 Hz and 1000 Hz
low-frequency jet exhaust noise.
(This figure is a 2-dimensional
representation of a 3-dimensional directivity pattern). It should be noted
that the noise level changes quite rapidly with angle in the region of the rear
lobes, particularly in the case of the LBPR engine, and that there is a
significant quiet zone directly behind the engine. This means that the noise
levels to the rear of a LBPR engine will be dependent on engine orientation,
both horizontally (side to side) as the aircraft moves down the runway, and
vertically (up and down) as it climbs. The result is that the noise level at a
distant observation point to the rear and side of the runway will vary with
Sharp,Gurovich,&Albee,WyleAcousQcsGroup,forNoiseAbatementOffice,SFO,2001
aircraft position along the runway as the angle to the aircraft changes. The
observers close to, and to the side
horizontal variation will be greatest for
of, the runway, and will diminish as the observation distance from the
runway increases. This effect will be less evident for a HBPR engine where
the rear lobe is less pronounced.
Theseareonlytwoofmanyfrequenciesgeneratedbyan
aircra&overflight
The characteristics of the directivity pattern of a LBPR jet engine at low (160
Hz) and high (1000 Hz) frequencies are given in Figure 2-6 for a DC-9 with
a hushkitted JT8D-7 engine2, showing that the majority of the noise radiated
to the rear of the aircraft is concentrated at low-frequencies.
100 Hz
1000 Hz
Figure 2-6. Directivity Patterns for a JT8D Engine at 100 Hz and 1000 Hz
WyleAcousQcsGrouptoSFONAO
2001
•  C-weighQngiseasilymeasuredbymostsound
levelmeters
•  C-weighQngispreferredoverA-weighQngto
describebackblastnoise
•  Backblastnoisecontainsasignificantamount
oflowfrequencyenergy.
8
16
31.5
63
125
250
500
1000
2000
4000
1/3-Octave Band Center Frequency, Hz
C-WeighQngisaCloserMatchtoActualAircra&Noise
Figure &SQllUNDERESTIMATESLowFrequencyNoise
2-2. Comparison of A- and C-Weighting Networks
Sharp,Gurovich,&Albee,WyleAcousQcsGroup,forNoiseAbatementOffice,SFO,2001
100
1s Leq, dB
80
60
Backblast Spectrum
40
A-Weighted Spectrum
C-Weighted Spectrum
20
0
8
16
31.5
63
125
250
500
1/3-Octave Band Center Frequency, Hz
1000
2000
4000
Whythisma\ers:
AirplaneenginenoiseA-&C-WeightedMeasurements
Low-Frequency
Aircraft Noise Research and Mitigation
01-21
September 2001
Sharp,Gurovich,&Albee,WyleAcousQcsGroup,forNoiseAbatementOffice,SFO,2001
110
Aircraft on
Runway
Aircraft
Airborne
90
80
70
60
C-weighted
50
A-weighted
Time (hh:mm:ss)
Figure 2-9. Noise Time History of a Single Aircraft Takeoff.
8:30:50
8:30:20
30
8:29:50
40
8:29:20
One-Second Leq, dB
100
LowFrequencyNoiseStudy
PartnershipforAiRTransportaQonNoise&EmissionsReducQon
FAA/NASA/TransportCanada
Figure 14. Spectrogram of sideline
noise during start-of-takeoff roll (event B777 285 1744) as measured
by Microphone 1 (see Table
2) 330 ft (100 m)from the centerline and 250 ft (76 m) from the
Hodgdon,Atchley,Bernhard
start of Runway 30.
April,2007
Figure 15. Mean Spectral Leq for all SOTR events for different microphone positions. The upper graph
shows the unweighted Leq as well as the typical background level. The lower graph shows the
A-weighted Leq.
34
significant contributor to low-frequency noise annoyance.
The thrust reverser Sound Exposure Levels (LE) for different single engine thrust ratings are
shown in Figure 19. The aircraft LowFrequencyNoiseStudy
in the third thrust category have the highest levels. This trend
is also seen inPartnershipforAiRTransportaQonNoise&EmissionsReducQon
Figure 20 which is a plot of the average LE as a function of aircraft type. The
B757 and B767 have the highestFAA/NASA/TransportCanada
levels, although B747, B777, and A330 aircraft have highest
maximum takeoff weight
Hodgdon,Atchley,Bernhard
April,2007
Figure 17. Spectrogram for thrust reverser event A330 292 1437 measured with Microphone 3 (see Table
1) 200 ft (61 m) from the centerline and 3000 ft (914 m) from the start of Runway 19R.
the curves at 250 Hz is due to ground interference. At lower frequencies,
noise levels decrease due only to the geometrical spreading of 6 dB per
doubling
of distance. This is a clear indication that distance is the only real
LowFrequencyNoiseDegradesDifferentlythanHigher
factor affecting the attenuation of low-frequency noise in a neutral
FrequenciesoverDistances
atmosphere.
Sharp,Gurovich,&Albee,WyleAcousQcsGroup,forNoiseAbatementOffice,SFO,2001
120
Sound Pressure Level, dB
100
80
60
40
250 ft
1000 ft
20
0
31.5
5000 ft
63
125
250
500
1000
2000
4000
8000
1/3-Octave Band Center Frequency, Hz
Figure 2-7. Backblast Noise Spectrum at Different Distances from the Aircraft
WorldHealthOrganizaQonpublicaQonon
CommunityNoise(Berglundetal.,2000)
•  "FornoisewithalargeproporQonoflow
frequencysoundsas'lllowerguideline(than
30dBA)isrecommended"
•  "ItshouldbenotedthatalargeproporQonoflow
frequencycomponentsinanoisemayincrease
considerablytheadverseeffectsonhealth"
•  "Theevidenceonlowfrequencynoiseis
sufficientlystrongtowarrantimmediate
concern"
WyleAcousQcsGrouptoSFONAO
2001
•  Meteorologicaleffectsarethemajorfactor
affecQngsoundpropagaQonoverlong
distances.Temperatureinversionsand
downwindpropagaQonwillincreaselowfrequencynoiselevels.
Figure 3.
LowFrequencyNoiseStudy
PartnershipforAiRTransportaQonNoise&EmissionsReducQon
Results of a parabolicFAA/NASA/TransportCanada
equation model of low-frequency sound propagation showing the
influence of a northeastHodgdon,Atchley,Bernhard
wind on the sound levels to the southwest of the runway. (From Ref.
4.)
April,2007
120
110
Oppressive Chest
Vibration Feeling
Sound Pressure Level, dB
100
90
Annoying/Objectionable
80
Inaudible
70
Detectable
60
50
8
16
31.5
63
125
250
1/3-octave Band Center Frequency, Hz
Figure 4. The Tokita and Nakamura's thresholds from along with data recorded outside the houses as
described in Ref. 4. The solid and dashed lines represent the highest 1/3-octave band sound
pressure levels recorded outside the house on two different days. The solid line corresponds
to a day when the wind was not from the northeast. The dashed line represents the levels on a
day with a northeast wind. (From Ref. 4.)
18
Weneednewdata
Wecan’tconvertA-weighteddatatoC-weighteddata
•  ComparingdBSPLanddBAordBC:
•  ThereisnoconversionformulaformeasureddBAordBC
valuestosoundpressureleveldBSPLorviceversa.Thatis
onlypossiblemeasuringonesinglefrequency.
•  NodBCmeasuredvaluescanbeconvertedtodBAvalues.
•  ThefrequencycomposiQonofthesignalisnotknown.
•  Theweightedsoundlevelisneitheraphysiologicalnora
•  physicalparameter. •  h\p://www.sengpielaudio.com/TableOfSoundPressureLevels.htm
h\p://www.prosoundweb.com/arQcle/print/
sound_level_meters_the_primer_what_how_why_techniques_more
CommunicatetoCongressional
RepresentaQves
1.
2. 
3. 
3. 
4. 
5. 
Requirefullspectralanalysisofoverflights,includingbyairplanemodeland speed.
Intheinterim,followrecommendaQonsofEPAtousemoremoderndata
gatheringandanalysis,andtheWHO,WyleReport,andFAA/Hodgdonreportto
useC-weightedmeasurementsofnoise.
EventhoughC-weighQngwilllikelyshowhigherdecibelimpactsinthe
community,donotraisealloweddecibellevelsto“compensate”forthis.
DisconQnueday/nightaveragesfordeterminingnoiseimpactsoncommuniQes.
UseactualC-weighteddiscreteeventsoverflightdatatodeterminenoise
impactsoncommuniQes
IntegrateC-weightednoisemeasurementswithscienQficfindingsofeffectsof
noiseonhealthandeducaQon,including,butnotlimitedtoeffectsofmid-and
low-frequencynoisefromaircra&overflights.
UnQlnoiseisaccuratelymeasuredandairspaceisappropriatelyreconfigured,
prohibitincreaseintotalnumberofflightsandmorestringentlyrestrict
nighrmeflights.
h\p://airportnoiselaw.org/
rs20531.html
• 
• 
• 
CongressionalResearchService
ReportforCongress
RS20531
• 
• 
• 
• 
• 
• 
NoiseAbatementandControl:
AnOverviewofFederalStandardsandRegula'ons
DavidM.Bearden
EnvironmentalInforma'onAnalyst
Resources,Science,andIndustryDivision
UpdatedApril7,2000
• 
InaddiQontotheabovelegislaQonregardingaircra&noise,onebillwasintroducedinthefirstsessionofthe106th
CongressthatwouldreestablishEPA'sOfficeofNoiseAbatementandControl.RepresentaQveNitaLowey
introducedtheQuietCommuniQesActof1999(H.R.2702)onAugust4,1999.Itwouldauthorize$21million
annuallyfromFY2000toFY2004tosupporttheacQviQesofanOfficeofNoiseAbatementandControl.The
reestablishedofficewouldemphasizenoiseabatementapproachesthatrelyonstateandlocalinvolvement,
marketincenQves,andcoordinaQonbetweenthepublicandprivatesectors.TheprimaryfuncQonsoftheoffice
wouldbetoprovidestateswithtechnicalassistanceandgrantstodevelopnoisecontrolprogramsandtoconduct
researchanddisseminateinformaQonontheeffectsofnoiseonhumanhealth.Thebillalsoincludesaprovision
thatwoulddirectEPAtostudytheFederalAviaQonAdministraQon'sselecQonofmethodologiesusedtomeasure
noise,thelevelatwhichairportnoiseaffectshumanhealth,andtheeffecQvenessofcurrentnoisecontrol
programsatairportsacrossthenaQon.EPAwouldberequiredtocompletethisstudywithin24monthsof
enactmentandrecommendnewmeasuresthatwouldreducetheimpactsofsuchnoiseonsurrounding
communiQes.
Aircra&NoiseMetrics
Aircra&Noise
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NewSecondhandSmoke
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