职业卫生与职业医学噪声

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1、NOISEFewnoisenaturallyoccurringinnaturehavethepotentialforphysiologicaldamagetohuman.Mostadverseeffectsofnoiseonhumansarelikelyofhumanoriginandcoincidewiththeadventofindustrialdevelopment.Thehazardsofnoiseareveryextensive,includingphysiologicalandpsychologicaleffectsinhumanb

2、odies.Healthhazardsfromnoiseariseprimarilyfromsources-associatedwithmanufacturing,recreation,transportation,andevenmechanizationwithinourhomesthatareintendedtomakelifemoreenjoyableanddailyworklessdifficult.▲BasicConception1.SoundThevibrationenergyspreadinginanelasticmedium(a

3、ir)canbeperceivedbyhumanearsasanaudiblesensation.Twofactors:soundsource;elasticmediumFrequency(f):Thenumberoftimesthatvibrationcompleteitscyclespersecond.Hertz(Hz)istheunitofsoundfrequency.SoundWave:20~20000HzInfrasonicwave/Infrasoundf<20HzUltrasonicwave/Ultrasoundf>20000Hz2

4、.NoiseNoiseisthesoundthatthesubjectiveisundesirableordislike.However,noisehasbeenthetraditionaltermusedinassociatedwithhealthhazard,sothistermwillbeusedheretorefertosoundthathasthepotentialforinflictinghearingimpairmentorotheradversephysiologicaland/orpsychologicalchangesinb

5、ody.Industrialnoise/Productivenoise:Allthesoundsarisingfromtherunningindustrialmachinery.Classification:-------bysource⑴Mechanicalnoise⑵Fluid-motivenoise⑶Electromagneticnoise------bytimedistribution⑴ContinuousnoiseSteadynoise(noisepressuredifference<5dB)/Non-steadynoise(>5dB

6、)⑵Intermittentnoise/ImpulsivenoiseContinuousperiodofnoise<0.5s;Intermittentperiodofnoise>1s;noisepressuredifference(rms)>40dB-------byfrequencycharacteristicsofsteadynoiseLow-frequencynoise(mainfrequency<300Hz)Middle-frequencynoise(mainfrequency300~800Hz)High-frequencynoise(

7、mainfrequency>800Hz)▲Physicalcharacteristicsandevaluation1.Soundintensity/Soundintensitylevel⑴Soundintensity(I):W/m2Soundintensityofthresholdofhearing(1000Hz):10-12W/m2(I0)[referencesound,referenceI]Soundintensityofthresholdofpaining(1000Hz):1W/m2(Ip)Ip/I0=1012⑵Soundintensit

8、ylevel(LI)ThelogarithmofaratiobetweenameasuringItothereferenceI.referenceI(