Background atmospheric CO₂ mixing ratios from individual flask air samples for Cold Bay, Alaska, U.S. Only measurements satisfying the data selection criteria fro background measurements are plotted. Consecutive background measurements are joined by lines. Background measurements interrupted by non-background measurements are not joined by lines.

Monthly atmospheric CO2 mixing ratios for Cold Bay, Alaska, U.S., expressed in parts per million (ppm) and
reported in the Scripps Institution of Oceanography X93 manometric mole fraction scale.  Annual values were
calculated by CDIAC for years with complete records.  Missing values are denoted by -99.99.



Year      Jan 	     Feb      Mar	April	  May	   June	     July      Aug     Sept	  Oct 	   Nov       Dec     Ann



1978    -99.99     -99.99   -99.99     -99.99   -99.99    -99.99    -99.99   -99.99   -99.99     333.99   336.60    338.25   -99.99
1979    340.06     340.84   341.69     342.91   342.57    338.62    332.43   327.94   331.18     336.82   339.06    339.75   337.82
1980    341.04     342.68   343.69     344.22   344.59    341.59    334.29   330.47   332.53     337.30   340.64    342.00   339.59
1981    343.75     344.91   345.58     346.25   345.20    341.85    335.53   330.99   333.54     339.48   342.48    343.90   341.12
1982    345.55     346.49   347.31     348.08   347.24    343.69    336.28   330.72   333.10     338.84   342.23    345.04   342.05
1983    346.58     346.25   346.29     347.21   347.05    343.73    336.66   332.78   337.08     343.46   345.69    346.05   343.24
1984    347.67     349.34   349.09     349.44   349.60    345.05    339.26   337.67   339.93     344.04   347.50    348.79   345.62
1985    348.85     349.64   351.39     352.33   351.90    349.07    343.99   338.01   338.85     344.45   347.56    349.07   347.09
1986    351.40     352.02   352.17     353.06   353.16    350.37    343.81   338.49   341.30     346.27   349.21    351.23   348.54
1987    352.19     352.60   353.62     354.89   354.89    351.87    345.20   339.44   341.44     348.72   352.59    353.55   350.08
1988    354.87     355.61   356.23     357.28   357.17    353.18    344.80   340.91   345.09     351.31   354.59    356.25   352.27
1989    357.52     358.05   359.23     360.55   359.47    355.59    347.90   342.68   346.23     352.10   355.44    358.19   354.41
1990    359.62     359.84   360.19     360.49   359.14    353.92    347.44   344.42   346.77     353.79   358.83    359.42   355.32
1991    359.33     360.50   361.68     362.92   362.37    357.21    350.97   348.79   349.70     354.17   359.28    360.76   357.31
1992    361.40     361.83   362.15     363.06   362.19    357.08    350.60   346.63   349.21     354.47   358.19    360.50   357.28
1993    361.60     361.97   362.21     362.68   361.97    358.01    353.14   348.66   349.78     355.50   358.76    359.95   357.85