Volcanoes don't product that much CO2, and degassing events that affect the ongoing monitoring are easily diagnosed based on meteorological factors and the actual record of the event.
CO2 is one of the three major volcanic gasses. (the others are SO2 and H2O)
Pu`u O`o, located on the Big Island (about 30 miles from CO2 observatory) has been “degassing” constantly since January, 1983. That is 24 years of nonstop eruption. The VOG (volcanic smog) is very similar to the air in Los Angeles, CA. People Kona side complain about VOG all the time, the trade winds carry it to Kona and then from Kona upslope to...Mauna Loa.
Today 12-4-07 the Kona winds are blowing and the VOG is all over the Hilo side covering Hilo town with a thick haze.
Take a look at the list of CO2 increase measurements and compare those before 1983 to those after 1983. There is a clear difference.
The Mauna Loa observatory claims that they are far from a pollution source are nonsense.
Alos CO2 constantly seeps upward through the rocks of volcanic cones such as Mauna Loa. This kills root systems keeping the upper slopes barren.