Degrees of deuteration, R_D(DCO⁺) (left column), R_D(DNC) (middle column), and R_D(DCN) (right column), with dust temperature (top row) and H₂ column densities (middle row; Bonne et al. 2023) and kinetic gas temperature (bottom row) in the DR21 filament. Each point corresponds to the pixel-wise deuteration derived from the J = 1−0 and J = 2−1 or J = 3−2 transitions of DCO⁺, DNC, and DCN where each of the species were detected at an rms noise level ≥4<σ_tot. The black line shows the running mean, while the purple ranges marks the standard deviation. The red and blue stars mark the surroundings of DR21 Main and DR21 (OH), respectively.