This VDAF web article gives further details on the first comparison results presented in the CO product readme file for the CO data product release. The main conclusion is that the product quality of this initial L2 CO dataset complies with the S5P mission requirements.
Current conclusions are however based on a limited initial dataset of measurements between November 2017 and 1 May 2018. The current validation analysis need to be extended over a full year of measurements, hence, a full cycle of key influence quantities, in order to enable detection of potential patterns, dependences, seasonal cycles and longer term features like drifts.