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1、Foghazeweather,causingalargeareaoflowvisibilityconditioninthecity.Inthemorningoratnightwhenrelativehumidityislarger,formingfog;Risingtemperatures,humiditydropsduringtheday,graduallyintoahaze.Thisphenomenonisduetoweatherandpollutionemissions.SinceJanuary9,2013,thecentralandeasternregionsinserioussmo
2、gandpollutionoftheday,thenationalmeteorologicalcentertoupgradetotheyellowfogbluewarningalert,13to10BeijingreleasedevenwhentheweatherfirsthazeorangealertinBeijing,inmid-january,Beijing'sairpollutionindexiscloseto1000.Fromthenortheasttothenorthwest,fromnorthChinatocentralresultinhuanghuai,jiangnanreg
3、ion,therewereawiderangeofsevereandseverepollution.雾霾天气,造成城市里大面积低能见度的情况。在早上或夜间相对湿度较大的时候,形成的是雾;在白天气温上升、湿度下降的时候,逐渐转化成霾。这种现象既有气象原因,也有污染排放原因。2013年1月9日以来,全国中东部地区陷入严重的雾霾和污染天中,中央气象台将大雾蓝色预警升级至黄色预警,13日10时北京甚至发布了北京气象史上首个霾橙色预警,一月中旬,北京的空气污染指数接近了1000。从东北到西北,从华北到中部导致黄淮、江南地区,都出现了大范围的重度和严重污染。Similaritiesbetweenfoga
4、ndhazearevisibilityobstruction.Butthereasonsfortheformationoffogandhazeandconditionsbutthere'sabigdifference.Fogisfloatingintheairofalargenumberofsmallwaterdropletsoricecrystals,formingconditionsrequiresahigherwatervaporsaturated.Appearedfogairhumidity,airrelativehumidityis100%,orcloserto100%.Appea
5、rwhenthefogeffectivehorizontalvisibilitytolessthan1km.Wheneffective1-10kmhorizontalvisibilityasmist.Foghaswiththedailyvariationofairhumidityandappearsoonerorlater,themorecommonoraddthick,relativelyreduceanddisappearphenomenonduringtheday.Ahazewhenairisrelativelydry,airrelativehumidityunder80%usuall
6、y.Itsformationisduetoalargenumberoftinyparticlesofdust,smoke,saltcrystalsevenlysuspendedintheair,makeeffectivehorizontalvisibilitytolessthan10kmairmixedcorrosionphenomenon,symbolsfor"up".Thediurnalvariationofthehazeisnotobviousingeneral.Whenairmasseswithoutbigchanges,theairmassisstable,continuetoap
7、pearforalongtime,sometimessustainablemorethan10days.Becausethehazeandmist,dust,flyingsand,dust,smoke,suchasaweatherphenomenon,floatingintheairforallthelargenumberofverysmalldustparticlesandsmokethateffectiv