Observed trends for CF3-containing compounds in background air at Cape Meares, Oregon, Point Barrow, Alaska, and Palmer Station, Antarctica

The concentrations of CF3-containing compounds in archived air samples collected at Cape Meares, Oregon, from 1978 to 1997, at Point Barrow, Alaska, from 1995 to 1998, and at Palmer Station, Antarctica, from 1991 to 1997, were determined by high resolution gas chromatography and high resolution mass spectrometry. The CF3-containing compounds measured by this method and discussed here are: the perfluorinated compound, C3F8 (FC 218); four perhalogenated compounds, CF3Cl (CFC 13), CF3CF2Cl (CFC 115), CF3CFCl2 (CFC 114a), and CF3Br (Halon 1301); and three hydrofluorocompounds, CF3H (HFC 23), CF3CH3 (HFC 143a), and CF3CH2F (HFC 134a). For four of these compounds, very few measurements have been previously reported. The atmospheric concentrations of all of the CF3-containing compounds continuously increased in time over the sample collection periods. From these data, the annual rates of emission into the atmosphere have been estimated. The emission rates fall into one of three distinct categories. The annual emission rates of C3F8, CF3H, CF3CH3, and CF3CH2F have continuously increased over the last two decades. That of CF3CFCl2 has decreased continuously. Emission rates for CF3Cl, CF3CF2Cl, and CF3Br reached maximum levels in the late 1980s, and have been decreasing in the 1990s. The emission rates of C3F8, CF3CH3 and CF3CH2F were nearly zero 20 years ago but have increased rapidly during the last decade.