You can find all of your historical measurements in your personalized dashboard at https://dashboard.airthings.com/.
Go to "Devices" in the menu -> scroll down to "Past measurements":
Historical data is not currently visible in the app. The app will only display your current measurements.
To access your historical data in the dashboard, simply use the same log-in credentials that you use for the Airthings App. Here you can see all of current and past measurement segments.
You can also read more about the online web dashboard here on the Airthings wesbite: https://www.airthings.com/dashboard