So, when using the local API on the airlink, I notice that the field 'last_report_time' updates on each call. It even seems like it updates every second, or at least every 2 or 3 seconds. I also notice that the 'pm_x_last' field, which represents the last reading made by the Airlink, changes slightly on most calls.
The question, how often does the Airlink do a reading that you would potentially want to retrieve? I currently have the readout interval at 15 seconds. I don't think I would want to go much lower in any case, but still interesting question.