Background atmospheric CO₂ mixing ratios from individual flask air samples for Guam. 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 Guam, 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



1979    -99.99     -99.99   339.20     339.81   340.07    339.72    338.46   337.00   335.42     334.56   335.90    337.95   -99.99
1980    339.15     340.23   340.93     341.62   342.58    342.44    341.22   339.80   337.98     337.13   338.37    339.25   340.06
1981    340.35     342.49   343.48     343.52   343.58    343.24    341.82   339.66   338.07     338.64   339.94    340.29   341.26
1982    341.49     343.17   343.48     343.66   344.17    343.33    341.52   338.70   336.55     336.77   338.61    340.37   340.99
1983    341.32     342.43   343.50     344.65   345.87    345.75    344.42   342.04   339.71     339.99   341.28    342.18   342.76
1984    343.42     344.44   345.08     346.32   347.18    346.84    345.91   344.26   341.89     341.80   343.08    343.89   344.51
1985    344.63     345.90   347.40     347.91   347.96    347.71    346.91   345.76   343.82     343.74   345.14    346.29   346.10
1986    347.61     348.12   348.56     349.84   350.65    349.91    347.79   345.64   344.51     344.76   346.20    347.23   347.57
1987    348.42     349.59   350.35     351.47   352.57    352.36    350.84   348.43   347.19     347.20   348.14    349.58   349.68
1988    350.80     352.13   353.09     353.82   354.48    354.07    352.96   352.17   351.02     349.75   349.95    350.95   352.10
1989    352.88     354.94   355.32     355.83   356.66    356.14    354.47   351.27   349.32     350.48   352.07    352.87   353.52
1990    354.24     355.54   356.24     356.63   357.14    357.13    354.18   350.28   350.15     351.72   352.91    354.40   354.21
1991    356.20     357.22   357.52     358.13   358.82    358.59    356.98   354.99   353.19     352.80   353.59    354.87   356.08
1992    355.90     357.13   358.20     358.75   359.70    359.13    357.01   354.83   352.76     352.67   354.19    355.89   356.35
1993    357.13     357.77   358.13     358.98   359.64    358.89    356.87   353.28   352.24     353.89   355.37    356.73   356.58