沙尘暴的形成需具备4个条件. 　　一是地面上的沙尘物质.它是形成沙尘暴的物质基础. 　　二是大风.这是沙尘暴形成的动力基础,也是沙尘暴能够长距离输送的动力保证. 　　三是不稳定的空气状态.这是重要的局地热力条件.沙尘暴多发生于午后傍晚说明了局地热力条件的重要性. 　　四是干旱的气候环境.沙尘暴多发生于北方的春季,而且降雨后一段时间内不会发生沙尘暴是很好的证据. 　　春季沙漠的边缘地区,由于长期干旱,而且地表少有植被覆盖,当有大风来临的时候地表的沙尘很容易被吹起且被输移,但由于沙子粒径较大,不易形成悬移(悬浮移动,是小颗粒物质保证长距离输移的必要条件),因此不能长距离输移,这也是距沙尘较远的地区只有降尘而少见扬沙的主要原因.如果风持续的时间很长,形成悬移的浮尘能够被输送到很远的地方,所经过的地区就会出现沙尘暴；当风速减弱到一定程度后,浮尘就会降落,该地就会出现降尘天气.如果此时降水,就会形成所谓的“泥雨”. 　　从沙尘暴形成过程所需的4个条件看,黄土高原、广袤的沙漠及由人为因素的破坏正处于荒漠化过程中的土地,北方春季末耕种的土地及处于施工过程中的基础设施(如高速公路等)为沙尘暴的发生提供了充分的物质源；而春季北方地区的干旱,又使沙尘暴发生的可能性增强；大风的产生是一种复杂的大气现象,主要是冷锋活动或经纬向环流调整作用的结果.由此可见沙尘暴的产生是多种复杂因素共同作用结果,人类活动对自然界的破坏导致土地荒漠化的加剧,对沙尘暴发生产生了极其重要的作用,而近几年全球干旱(其原因目前尚未知)等异常天气现象也对沙尘暴的发生起了不可估量的作用.所以说人类活动对沙尘暴的产生只起到一定作用,并不能说沙尘暴就是人为因素造成的. 　　Theformationofthesandstormtohavethefourconditions. 　　Oneisthedustonthegroundmaterial.Itisthematerialbasisofformsandstorm. 　　2itiswinds.Thisisthepoweroftheformation,isfundamentaltothepowerofthesandstormlong-distancetransportofguarantee. 　　Threeisnotstableaircondition.Thisisanimportantlocalthermalconditions.Sandstormoccursmoreoftenintheafternoonthatincorporatestheeveningtheimportanceofthermalcondition. 　　Fouristhedryweatherenvironment.Borninthenorthofthesandstormmultiplespring,andrainafteraperiodoftimewithinawon'thappenverygoodevidenceisduststorms. 　　Theedgeofthedesertinthespring,duetolongdrought,andsurfacevegetationcover,whenthereislittlewindcomesonthesurfaceoftheearthiseasytobeblowingdustandsand,butduetolosemovelargeparticlesize,isformednoteasilymovable(suspensionmovement,itissmallparticlematerialguaranteetolosethenecessaryconditionsoflongdistancemove),andthereforecannotmovelonglost,thisisfarfromthedustinthedustandrareonlymicrometeorologymainreason.Ifthewindlasttimeisverylong,formthedustsuspendedloadscanbetransportedtoaveryfarplace,throughwhichareaswillappearsandstorm;Whenthewindsweakentocertaindegree,floatingdustwillthelanding,thedustweatherwillappear.Iftheprecipitation,canformtheso-called"NiYu". 　　Theformationprocessfromthefourconditionslook,theloessplateauandvastdesertandbythedestructionofthehumanfactorsintheprocessofdesertificationisinthelandofthenorth,attheendofthespringfarminglandandintheconstructionprocessofinfrastructure(suchashighspeedroad,etc.)fortheduststormoccurrenceprovidingfullsourcematerial;Andthespringdroughtinthenorth,andthelikelihoodofthesandstormstrengthened;Thewindsgeneratedisacomplexphenomenon,mainlyisthecoldairactivitiesortothecirculationoftheregulatoryrolelongituderesults.ThisshowsthegenerationofsandstormisDuoZhongcomplexfactorsresultsofhumanactivityonthenaturalworldtodisruptionofthedesertificationintensifies,duststormshappentohaveanimportantrole,andinrecentyearstheglobaldrought(thecauseisn'tyetknown)abnormalweatherphenomenonalsototheduststormoccurrencehaveplayedanimportantrole.Sothathumanactivitiesforthegenerationofduststormsonlyplayarole,andcan'tsayduststormsarecausedbyhumanfactors.