Cumulative distribution function (CDF) of dust temperature and H₂ column density where DCO⁺ (purple), DNC (orange), or DCN (blue) is detected in the DR21 filament. The dust temperatures and H₂ column density maps are taken from Bonne et al. (2023). The horizontal dashed lines marks the mean dust temperature or column density of the sampled distributions, colorized with the respective detected molecular ratio.