That leaves us with Point Barrow, arguably the only CO measurements are unlikely to be influenced by magmatic gas plumes.
Although you might imagine that there is no air in the mantle, the chemical conditions favour oxidation, and shortages of oxygen ions are rare enough to ensure a strong presence of CO rather than a representative sample of the Troposphere.
For example, Cape Kumukahi is located in a volcanically active province in Eastern Hawaii, while Mauna Loa Observatory is on Mauna Loa, an active volcano - both observatories within 50km of the highly active Kilauea and its permanent 3.2 Mt COpa plume.
Given the more than 3 million volcanoes worldwide indicated by the work of Hillier & Watts (2007), one might be prone to wonder about the statistical significance of Gerlach's seven subaerial volcanoes and three hydrothermal vent sites.
If the statement of the USGS concerning volcanic CO is any indication of the reliability of expert consensus, it would seem that verifiable facts are eminently more trustworthy than professional opinion. Kerrick (2001) takes a grand total of 19 subaerial volcanoes, which on p.
This estimate includes both subaerial and submarine volcanoes, about in equal amounts.
In point of fact, the total worldwide estimate of roughly 55 Mt Cpa is by one researcher, rather than "scientists" in general.
While volatiles trapped in the remaining crustal residue are ultimately assimilated into the mantle, lighter volatiles from the crustal melt are fractionated and float up towards the surface to feed plate margin volcanoes.
Volatiles, such as CO is the second most abundantly emitted volcanic gas next to steam.
In any case, the strong circumpolar winds that delay mixing will inevitably concentrate Antarctica's volcanic CO emissions over the Antarctic continent, including Amundsen Station.