A capsule of a volatile substance distribution system is configured for use with a base unit having a fan and an air outlet configured to direct air driven by the fan away from the base unit. The capsule includes a housing that extends along a longitudinal axis between a first end and a second end. The first end defines an inlet port and the second end defines an outlet port. The housing houses a volatile substance member. The capsule further includes an outlet seal member that seals and unseals the outlet port. The housing, when engaged with the base unit and with the outlet seal member in the unsealed position, is configured to receive the air from the air outlet that flows into the inlet port, past the volatile substance member, and out of the outlet port.