Thanks for pointing out that site. That is an awesome map. I find it very interesting / telling that the US has bright red areas for CO2 as well but all of them are at major shipping ports and in the ocean. Not surprising seeing how much pollution shipping creates.

Why does the Grand Canyon have such a huge pocket of CO? It's over 1200ppbv. Is there currently a forest fire there? The air quality there looks as bad as over Staten Island or some Chinese cities.

That pocket looks rather like an anomaly in the data. There is a very large coal-fired power plant (Navajo Generating Station) near Page, Arizona, though.

There's a major fire south of that, in the middle of the state. But not right there, so far as I know.

Great site ... thanks for this reference!