Atmospheric　particulate　matter　is　the　primary　pollutant　affecting　the　ambient　air　quality　in　most　Chinese　cities.　In　recent　years,　with　the　progress　of　monitoring　technology　and　improvement　in　sampling　equipment,　the　relevant　research　objects　gradually　shift　from　larger　particle　sizes　(PM10　and　PM2.5)　to　smaller　particle　size　(PM1).　The　carbonaceous　component　is　an　important　part　of　atmospheric　particulate　matter.　Taking　Beijing　as　the　research　area,　sampling　for　PM2.5　and　PM1　was　conducted　in　July　and　October　of　2016,　and　January　and　April　of　2017　as　representative　months　of　four　seasons.　Mass　concentrations　and　seasonal　variation　characteristics　for　PM2.5　and　PM1　were　analyzed.　The　two-layer,　nested,　meteorology-air　quality　coupling　model　system　(WRF-CMAQ)　was　used　to　model　air　circulation　during　the　sampling　period　and　thus　analyze　the　source　contributions　for　PM2.5　and　PM1.　The　factor　analysis　method　was　also　used　to　analyze　the　source　apportionment　of　carbonaceous　components.　The　results　are　as　followed:　the　mass　concentrations　of　PM2.5　and　PM1　showed　an　increasing　trend　by　spring,　summer,　autumn　and　winter.　PM1　was　the　main　part　of　PM2.5,　and　with　the　increasing　frequency　of　haze　in　autumn　and　winter,　the　mass　concentration　ratio　of　PM1/PM2.5　became　significantly　higher.　The　authors　contend　that　secondary　pollution　exists　in　Beijing＇s　atmosphere,　and　SOC　is　more　likely　to　accumulate　in　smaller　particle　size.　Widespread　coal　combustion,　vehicle　emission,　residential　emission　source　and　biomass　combustion　emissions　are　the　major　contributors　to　atmospheric　particulates,　while　gasoline　engine　exhaust,　diesel　vehicle　exhaust,　biomass　combustion　and　coal　combustion　emission　are　the　main　source　of　carbonaceous　components　in　PM2.5　and　PM1　in　Beijing.　©　2018,　Science　Press.　All　right　reserved.