I wanted to see if it is easy to load only the historical data of Frankfurt, or if it is easier to load all historical data and then filter it later.
On this matter, I want to link to Air quality information for specific regions where we show different examples how this can happen and which might be a starting point for others.
The answer is: We put in some efforts to bring geospatial query features into the mix based on importing location data into PostGIS. So, reusing this will be the most convenient way to query data by geographic regions.
When using luftdatenpumpe for processing the data, timeseries data (measurement values) will go into InfluxDB while geospatial data (station/location information) will go into PostGIS.