Line luminosities of far-IR lines along the DR21 Main outflow. The absorption-corrected luminosity of [O I] is shown in violet and the measured values from FIFI-LS in blue. The total line luminosities of [C II], CO, OH, and [O III] are in yellow, orange, red, and green, respectively. They are normalized to the total luminosity of absorption-corrected [O I] luminosity – [O I]*. In addition, OH is scaled up by a factor of 5 for better visualization. The X-axis shows the offset from the adopted center of DR21 Main; see also Fig. 7.