This read-only OCTET STRING (up to 30 bytes) reports the scheduled date on which the passive air filter is due for replacement, computed from the last reset and the configured monthly frequency. An admin checks this date to schedule a physical maintenance visit before the filter becomes due, avoiding the airflow restriction and rising internal temperatures that come from an overdue filter. For example, seeing passiveAirFilterReplaceDate only a week away prompts the admin to add a filter swap to that week's data-center maintenance rounds.