re:: “(…) sparse ground station distribution in most regions”
Proposal:
If citizens themselves install data points via their own sensors on their houses, the network of data points can be more finely meshed and meaningful, provided that the comparability of the data quality is guaranteed.
Proof:
Both 
Fab Lab Barcelona as well as Lichen Social Innovation recently shared with us proof that this is possible.
Uptake:
Why don’t municipalities simply roll out the allocation of sensors calibrated according to the EU / municipal / legislative requirements? - What is your estimate and/or experience @Stakeholders @CitizensTestingGroup ?