This　study　made　a　field　VOCs　(volatile　organic　compounds)　measurement　for　a　petroleum　refinery　in　Beijing　by　determining　56　PAMS　VOCs,　which　are　demanded　for　photochemical　assessment　in　US,　and　obtained　the　characteristics　of　VOCs　emitted　from　the　whole　refinery　and　from　its　inner　main　devices.　During　the　monitoring　period,　this　refinery　brought　about　an　average　increase　of　61　ppbv　in　the　ambient　TVOCs　(sum　of　the　PAMS　VOCs)　at　the　refinery　surrounding　area,　while　the　background　of　TVOCs　there　was　only　10-30　ppbv.　In　chemical　profile,　the　VOCs　emitted　from　the　whole　refinery　was　characteristic　by　isobutane　(8.7%),　n-butane　(7.9%),　isopentane　(6.3%),　n-pentane　(4.9%%),　n-hexane　(7.6%),　C6　branched　alkanes　(6.0%),　propene　(12.7%),　1-butene　(4.1%),　benzene　(7.8%),　and　toluene　(5.9%).　On　the　other　hand,　the　measurement　for　the　inner　5　devices,　catalytic　cracking　units　(CCU2　and　CCU3),　catalytic　reforming　unit　(CRU),　tank　farm　(TF),　and　wastewater　treatment(WT),　revealed　the　higher　level　of　VOCs　pollutions　(about　several　hundred　ppbv　of　TVOCs),　and　the　individual　differences　in　VOCs　chemical　profiles.　Based　on　the　measured　speciated　VOCs　data　at　the　surrounding　downwind　area,　PMF　receptor　model　was　applied　to　identify　the　VOCs　sources　in　the　refinery.　Then,　coupling　with　the　VOCs　chemical　profiles　measured　at　the　device　areas,　we　concluded　that　CCU1/3　contributes　to　25.9%　of　the　TVOCs　at　the　surrounding　downwind　area　by　volume,　followed　by　CCU2　(24.7%),　CRU　(18.9%),　TF　(18.3%)　and　WT　(12.0%),　which　was　accordant　with　the　research　of　US　EPA　(2008).　Finally,　ozone　formation　potentials　of　the　5　devices　were　also　calculated　by　MIR　technique,　which　showed　that　catalytic　cracking　units,　accounting　for　about　55.6%　to　photochemical　ozone　formation,　should　be　given　the　consideration　of　VOCs　control　firstly.　(C)　2014　Elsevier　Ltd.　All　rights　reserved.