Gas phase and solid-state C/O ratios at various radii in a protoplanetary disk, based on the trapping and release of CO, CO₂, and H₂O. The original model of Öberg et al. (2011b) without trapping is presented in black. The updated model takes the trapping of CO and CO₂ in H₂O ($F_{{\mathrm{H}}_2\mathrm{O}}$(CO,CO₂)) and CO in CO₂ ($F_{{\mathrm{C}\mathrm{O}}_2}$(CO)) at different fractions into account (blue, green, and red lines) and shows that the solid C/O ratio is strongly affected. The snowlines of CO, CO₂, and H₂O are indicated.