Quantitative Volcanic Ash Concentration Information Notification

The notification and way to retrieve the Quantitative Volcanic Ash Concentration Information Message e.g. the URL, or the volcano number. The message will include:
- publication time
- operation e.g. if it is an update or a new message
The message can include:
- identifier of the VAAC
- event type e.g. if it is live
Note: an example of the structure of the URL that is used to retrieve the QVA in IWXXM format using an EDR implementation: https://{organizaton URL}/QVACI_Iwxxm/Locations/{VolcanoNumber} Note: the URL, if provided, could be a request formatted for the Quantitative Volcanic Ash Concentration Information Subscription and Request Service Request Interface.