AbstractOrganophosphorus compounds (OPs) being applied as flame retardants and plasticizers were investigated in airborne particles over the Pacific, Indian, Arctic and Southern Ocean. Samples taken during two polar expeditions in 2010/11, one from East Asia to the high Arctic (CHINARE 4) and another from East Asia toward the Indian Ocean to the Antarctic (CHINARE 27), were analyzed for three halogenated OPs (tris(2–chloroethyl) phosphate (TCEP), tris(2–chloroisopropyl) phosphate (TCPP) and tris(1,3–dichloro–2–isopropyl) phosphate (TDCP)), four alkylated OPs (tri–n–butyl phosphate (TnBP), tri–iso–butyl phosphate (TiBP), tris(2–butoxyethyl)phosphate (TBEP) and tris(2–ethylhexyl) phosphate (TEHP)) and triphenyl phosphate (TPhP). The sum of the eight investigated OPs ranged from 230 to 2900 pg m–3 and from 120 to 1700 pg m–3 during CHINARE 4 and CHINARE 27, respectively. TCEP and TCPP were the predominating compounds, both over the Asian seas as well as in the polar regions with concentrations from 19 to 2000 pg m–3 and 22 to 620 pg m–3, respectively. Elevated concentrations were observed in proximity to the Asian continent enhanced by continental air masses. They decreased sharply toward the open oceans where they remained relatively stable. This paper shows the first occurrence of OPs over the global oceans proving that they undergo long–range atmospheric transport over the global oceans toward the Arctic and Antarctica.