A Public service announcement or PSA is a short commercial-type message, often done by a celebrity, to explain or emphasize a point. The network or station transmitting the PSA does not receive payment for the transmission, as opposed to a commercial or info-mercial. 24 has produced several such announcements over the course of the series.
During the fourth season of 24, Kiefer Sutherland appeared in a PSA organised in association with The Council on American-Islamic Relations, explaining that the day's events were fictitious and in no way suggestive of any real terrorist cells being formed by immigrant or naturalized Americans. This was in response to several groups' public messages that Americans of Arab descent or appearance were being targeted for harassment due to the depictions of characters on 24.
For the sixth season, Kiefer Sutherland released another PSA speaking about the problem of global warming, delivered from the White House set. He informed viewers that the show would be taking creative new steps in the next year to more efficiently produce the show and reduce the carbon footprint. He urged viewers to visit the Fox website for more information. This PSA was included on the Region 1 DVD release of the season.
During the seventh season, various main cast members, including Kiefer Sutherland, Cherry Jones, Mary Lynn Rajskub, and Carlos Bernard appeared in PSAs advocating the carbon-neutrality of the production of 24.