Results of H₂CO abundance models: spectra integrated over the emission rectangle of the observations for different abundances for model 1 (purple), model 2 (green), and model 3 (red) for abundances 10^-7 (dashed), 10^-8 (solid), and 10^-9 (dotted). The black spectrum represents the observational data. Abundances for model 2 are multiplied with 10^-4 to translate the abundance w.r.t. CO to H₂. The top figure shows the original models. The bottom figure shows the model spectra scaled to match the total flux of the observations.