英语作文噪音

NoisePollution噪音污染

Noiseisamongthemostpervasivepollutantstoday.Noisefromroadtraffic,jetplanes,jetskis,garbagetrucks,constructionequipment,manufacturingprocesses,lawnmowers,leafblowers,andboomboxes,tonameafew,areamongtheaudiblelitterthatareroutinelybroadcastintotheair.

Noisenegativelyaffectshumanhealthandwell-being.Problemsrelatedtonoiseincludehearingloss,stress,highbloodpressure,sleeploss,distractionandlostproductivity,andageneralreductioninthequalityoflifeandopportunitiesfortranquillity.

Weexperiencenoiseinanumberofways.Onsomeoccasions,wecanbeboththecauseandthevictimofnoise,suchaswhenweareoperatingnoisyappliancesorequipment.Therearealsoinstanceswhenweexperiencenoisegeneratedbyothersjustaspeopleexperiencesecond-handsmoke.Whileinbothinstances,noisesareequallydamaging,second-handnoiseismoretroublingbecauseithasnegativeimpactsonusbutisputintotheenvironmentbyothers,withoutourconsent.

Noisepollutionisnoteasilydefined.Partofthedifficultyliesinthefactthatinsomewaysitisdifferentfromotherformsofpollution.Noiseistransient;oncethepollutionstops,theenvironmentisfreeofit.Thisisnotthecaseforchemicals,sewage,andotherpollutantsintroducedintotheair,soil,orwater.

Thedefinitionofnoiseitselfishighlysubjective.Tosomepeopletheroarofanengineissatisfyingorthrilling;toothersitisanannoyance.Loudmusicmaybeenjoyableoratorment,dependingonthelistenerandthecircumstances.Broadlyspeaking,anyformofunwelcomesoundisnoisepollution,whetheritistheroarofajetplaneoverheadorthesoundofabarkingdogablockaway.

Theactualloudnessofasoundisonlyonecomponentoftheeffectithasonhumanbeings.Otherfactorsthathavetobeconsideredarethetimeandplace,theduration,thesourceofthesound,andwhetherthelistenerhasanycontroloverit.Mostpeoplewouldnotbebotheredbythesoundofa21-gunsaluteonaspecialoccasion.Ontheotherhand,thethump-thumpofaneighbour'smusicat2a.m.,evenifbarelyaudible,couldbeamajorsourceofstress.

Thedecibel(dB)(分贝)isameasureofsoundintensity;thatis,themagnitudeofthefluctuationsinairpressurecausedbysoundwaves.Infact,anincreaseofjust3dBmeanstwiceasmuchsound,andanincreaseof10dBmeanstentimesasmuchsound.

Asoundpressurelevelof0dBrepresentsthethresholdofhearinginthemostsensitivefrequencyrangeofayoung,healthyear,whilethethresholdsofticklingorpainfulsensationsintheearoccuratabout120to130dB.Thereisfairlyconsistentevidencethatprolongedexposuretonoiselevelsatorabove80dBcancausedeafness.Theamountofdeafnessdependsuponthedegreeofexposure.

Noisecancauseannoyanceandfrustrationasaresultofinterference,interruptionanddistraction.Exposuretonoiseisalsoassociatedwitharangeofpossiblephysicaleffectsincluding:colds,changesinbloodpressure,othercardiovascularchanges,increasedgeneralmedicalpracticeattendance,problemswiththedigestivesystemandgeneralfatigue.