Subscribers can opt out of any non-critical alert topic. This flexibility ensures that subscribers are only receiving the informational alerts that they have an interest in. Subscribers can not opt out of Critical Severity alerts.
1) To opt out of any Informational Severity notification type a subscriber can do so by opening the menu on the mobile or web app and selecting My Topics.
2) The subscriber can unsubscribe from Public Topics that are not of interest. There is no option to unsubscribe from Critical Notification Priority alerts.