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

The concentrations of CF(3)-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 CF(3)-containing compounds measured by this method and discussed here are: the perfluorinated compound, C(3)F(8) (FC 218); four perhalogenated compounds, CF(3)Cl (CFC 13), CF(3)CF(2)Cl (CFC 115), CF(3)CFCl(2) (CFC 114a), and CF(3)Br (Halon 1301); and three hydrofluorocompounds, CF(3)H (HFC 23), CF(3)CH(3) (HFC 143a), and CF(3)CH(2)F (HFC 134a). For four of these compounds, very few measurements have been previously reported. The atmospheric concentrations of all of the CF(3)-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 C(3)F(8), CF(3)H, CF(3)CH(3), and CF(3)CH(2)F have continuously increased over the last two decades. That of CF(3)CFCl(2) has decreased continuously. Emission rates for CF(3)Cl, CF(3)CF(2)Cl, and CF(3)Br reached maximum levels in the late 1980s, and have been decreasing in the 1990s. The emission rates of C(3)F(8), CF(3)CH(3) and CF(3)CH(2)F were nearly zero 20 years ago but have increased rapidly during the last decade.

Improvements in the detection and analysis of CF3-containing compounds in the background atmosphere by gas chromatography-high-resolution mass spectrometry.

An improved method for the gas chromatography/mass spectrometry analysis of CF3-containing compounds in air is described. This method replaces a GS-Q porous layer open tubular (PLOT) column previously used with a 30 m x 0.32 mm GS-GasPro PLOT column. For this exceedingly volatile set of compounds the GS-GasPro column provides improved peak shapes, better signal-to-noise responses and no coelution of compounds. These improvements have allowed eleven CF3-containing compounds to be detected in background air, including CF4 (FC 14), C2F6 (FC 116), CF3Cl (CFC 13), CF3H (HFC 23), CF3Br (Halon 1301), C3F8 (FC 218), CF3CF2Cl (CFC 115), CF3CHF2 (HFC 125), CF3CH3 (HFC 143a), CF3CH2F (HFC 134a), and CF3CFCl2 (CFC 114a). Three of these compounds have not been previously detected in background air, to our knowledge. Quantitative determinations for each of these compounds in the background atmosphere of Montana are also reported.