These detailed historical data logs are held in the Pro/Nodes internal memory for up to 5 years. At any point here-within, it is possible to retrieve all of your Pro/Node's data by wirelessly downloading the comma delimited .txt file, via Samba. Detailed information on how to do that here: http://support.airvisual.com/knowledgebase/articles/946228-download-the-airvisual-node-pro-s-data-using-samba
It is also possible to receive your Pro/Node's measurements in real-time via the AirVisual mobile app. The app updates every minute, so that you are constantly aware of the air quality readings of your Pro/Node.