Air collects music by two Danish composers, Bent Sørensen and Hans Abrahamsen, played by the Norwegian accordionist Frode Haltli, for whom most of it was written. Heard with string orchestra, with string quartet and alone, Haltli treats the accordion as an instrument of fine tone control and very soft dynamics, far from its folk image. All four pieces date from between 2005 and 2010.

Sørensen's It is Pain Flowing Down Slowly on a White Wall (2010), for accordion and string orchestra, is played with the Trondheim Soloists under their artistic director Øyvind Gimse. Abrahamsen's Three Little Nocturnes (2005) bring in the Arditti Quartet, while Air (2006) and Sørensen's Sigrid's Lullaby (2010) are solos. The album was recorded in October and November 2014 at Selbu Kirke in Norway, with Sean Lewis as engineer and Manfred Eicher as executive producer. Haltli and Paul Griffiths wrote the liner notes.

Sørensen's concerto opens with a hesitant A from an offstage solo violin, and the orchestra wakes slowly around it before the accordion slips into the sound almost as a guest. Haltli says Sørensen shaped his development as a player, and this 21-minute piece explores exactly that territory of quiet nuance. For Air, Abrahamsen returned at Haltli's suggestion to his early solo work Canzona and reworked it into a new piece "characterized by a great sense of peace and a cohesive form". Its outer sections are built on held chords, with a dance-like passage between them. The Three Little Nocturnes run from a gentle Andante amabile through an agitated Allegro appassionato to a last movement marked to proceed with hesitant, dragging steps.

In BBC Music Magazine, Kate Wakeling wrote that "the pairing of strings and accordion proves a glorious combination" and found the two ensemble works the most affecting. John Garratt of PopMatters (2016) said of the music: "It is highly original but puts no distance between the music and the listener." Writing in the Frankfurter Allgemeine Zeitung, Jan Brachmann called Haltli and the Trondheim Soloists the composer's ideal interpreters.

This is the CD edition, ECM New Series 2496, released on 26 August 2016.