Average integrated intensities of HCO⁺ (in blue), H₂CO (in red), and N₂H⁺ (in green) across the interaction region in the western lobe of DR2l. Intensities are integrated from −70 to 70, from −20 to 20, and from −20 to 10 km s⁻¹ for HCO⁺, H₂CO, and N₂H⁺, respectively. The x-axis shows the distance in arcseconds covering the extent of the relevant region where the outflow interacts with a dense structure (marked also in Fig. 11). The orange rectangle shows the area actively affected by the interaction. The intensities for H₂CO and N₂H⁺ are scaled up by a factor of 8 in order for their distributions to be more easily comparable.