This sound recording is free to use and reuse. You can copy, modify, distribute and perform the work, even for commercial purposes, all without asking permission. Attribution is recommended but not required.
Also see this detailed guide covering the copyright and ethical considerations of digital sampling of audio and video materials.
Why is this free to use?
In 2007, Tony Schwartz's entire body of work was acquired by the Library of Congress, thus the Library reserves the right to make his recordings available for reuse as long as those recordings do not contain embedded material to which Schwartz did not own the copyright. Therefore, Citizen DJ excludes: (1) recordings that contain music or speeches from identifiable or named performers and composers, (2) radio broadcasts, and (3) commercials.