APEX SEPIA/B5 line survey of W Aql. Labels show the carrier molecule of the indicated emission. Red labels indicate tentative or unidentified detections. Purple labels (Im(...)) pertain to emission contaminating the signal from the image sideband (see Sect. 2). For visibility, some parts of the survey were rescaled to fit the vertical scale. The colour coding of the spectrum corresponds to the following scale factors: (black) 1; (green) 1/5. We note that the labellingat frequencies above 209.0 GHz is based on identifications in the PI230 spectrum and is shown here only for reference.