Threshold Set Assignment Date

The assignedAt timestamp on a ThresholdSetAssignment documents when your organization began applying a particular regulatory standard to a site's exceedance detection. This is important for audit purposes: if a regulator asks when a specific standard was in effect for your site, assignedAt provides the authoritative answer. It also helps compliance staff determine which ThresholdSetAssignments were active on any historical sampleDate, ensuring that exceedance reviews use the limits that were actually in place at the time of the sampling event rather than the limits in effect today.