This disclosure includes wound dressings and systems for effluent management of topical wound therapy and related methods. Some devices, which are configured to dilute therapeutic gas effluent flowing from a dressing, comprise a therapeutic gas source configured to provide therapeutic gas to the dressing; a container comprising a sidewall that defines a chamber configured to receive therapeutic gas effluent from the dressing; a negative pressure source configured to be coupled to the container such that the negative pressure source can be activated to draw fluid from the dressing through the chamber of the container; and a diluent gas source configured to deliver a diluent gas to dilute therapeutic gas effluent before the therapeutic gas effluent enters the negative pressure source.