Actually, since they're useful to libs (liars and charlatans), it's pretty much a given that they're NOT any of that stuff.
CO2 measurements are about the most well-studied and repeated part of the global warming controversy. People who point out that Mauna Loa is contaminated by a volcano have not looked at the science. There are literally zero locations where CO2 has been measured that do not display the rise and seasonal cycle (peak of CO2 around April before the northern hemisphere vegetation kicks in and starts drawing it down).