| Carbon | |||||||||
| Carbon | tetra- | Methyl | CFC- | Total | Nitrous | Meth- | |||
| dioxide | chloride | chloro- | 11 | CFC- | CFC- | chlorine | oxide | ane | |
| Year | (CO2) | (CCl4) | form | (CCl3F) | 12 | 113 | (gas) | (N2O) | (CH4) |
| ppm | ppt | ppt | ppt | ppt | ppt | ppt | ppb | ppb | |
| 1970 | 326 | na | na | na | na | na | na | na | na |
| 1971 | 326 | na | na | na | na | na | na | na | na |
| 1972 | 327 | na | na | na | na | na | na | na | na |
| 1973 | 330 | na | na | na | na | na | na | na | na |
| 1974 | 330 | na | na | na | na | na | na | na | na |
| 1975 | 331 | na | na | na | na | na | na | na | na |
| 1976 | 332 | na | na | na | na | na | na | na | na |
| 1977 | 334 | na | na | na | na | na | na | na | na |
| 1978 | 335 | 88 | 58 | 139 | 257 | na | 1,457 | 298 | na |
| 1979 | 337 | 88 | 63 | 147 | 272 | na | 1,529 | 299 | na |
| 1980 | 339 | 90 | 71 | 158 | 289 | na | 1,622 | 299 | na |
| 1981 | 340 | 91 | 76 | 166 | 305 | na | 1,698 | 299 | na |
| 1982 | 341 | 93 | 82 | 175 | 325 | 26 | 1,871 | 301 | na |
| 1983 | 343 | 94 | 86 | 182 | 341 | 28 | 1,945 | 302 | na |
| 1984 | 344 | 95 | 89 | 190 | 355 | 31 | 2,024 | 303 | na |
| 1985 | 346 | 97 | 93 | 200 | 376 | 36 | 2,127 | 304 | na |
| 1986 | 347 | 98 | 97 | 209 | 394 | 40 | 2,222 | 305 | 1,600 |
| 1987 | 349 | 100 | 100 | 219 | 411 | 48 | 2,321 | 306 | 1,611 |
| 1988 | 351 | 101 | 104 | 231 | 433 | 53 | 2,432 | 306 | 1,619 |
| 1989 | 353 | 101 | 108 | 240 | 452 | 59 | 2,531 | 306 | 1,641 |
| 1990 | 354 | 102 | 111 | 249 | 469 | 66 | 2,626 | 307 | 1,645 |
| 1991 | 356 | 102 | 114 | 254 | 483 | 71 | 2,691 | 307 | 1,657 |
| 1992 | 356 | 101 | 118 | 260 | 496 | 77 | 2,762 | 308 | 1,673 |
| 1993 | 357 | 101 | 112 | 262 | 508 | 81 | 2,768 | 308 | 1,678 |
| 1994 | 359 | 92 | 106 | 262 | 512 | 81 | 2,774 | 309 | 1,673 |
| 1995 | 361 | 99 | 97 | 261 | 519 | 82 | na | 309 | 1,681 |
| 1996 | 363 | 98 | 85 | 261 | 524 | 82 | na | 310 | 1,683 |
| 1997 | 364 | 97 | 73 | 260 | 528 | 83 | na | 311 | 1,690 |
| 1998 | 367 | na | na | na | na | na | na | na | na |
| 1999 | 368 | na | na | na | na | na | na | na | na |
Sources: Carbon dioxide: Keeling, C.D. and T.P. Whorf, Scripps Institution of Oceanography, Atmospheric CO2 Records from Sites in the SIO Air Sampling Network. In: Trends: A Compendium of Data on Global Change (an Internet accessible numerical database) (Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, TN, 2000).
Trace gases: Prinn, R.G., et al., Continuous High Frequency Gas Chromatographic Measurements of CH4, N2O, CFC-11, CFC-12, CFC-113, Methyl Chloroform, and Carbon Tetrachloride From the ALE/GAGE/AGAGE Network Station at Cape Grim, Tasmania (an Internet accessible numerical database) (Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, TN, 1998).
Notes: ppm = parts per million. ppb = parts per billion. ppt = parts per trillion. CFC = Chlorofluorocarbon. All estimates are by volume. na = not available.
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