After powering up, the Disconnected CO2 Data Logger will begin logging CO2 data with a timestamp to the Adalogger FeatherWing's SD card every 30 seconds.
When you've finished logging, you can import the text file from the SD card, which is comma delimited, to your preferred spreadsheet editor to create charts to visualize your data.
This line graph was created with Google Sheets and shows the CO2 data in a public space over the course of a day. You can tell when a larger crowd gathered in the afternoon.
By collecting data in this way, you can really do whatever you want with it. It isn't tied to a service and the text file format makes it so that it travels easily between applications.