Example of SED models for four regions of the sample catalogued as filled (top left), mixed (top right), shell (bottom left), and clear shell (bottom right). These regions correspond to regions 5, 98, 45, and 78 in Table B.1 in Paper I, respectively. Region 98 is the most luminous H ii region in M 33, NGC 604. The best-fit SED (continuous black line) is obtained assuming a 4 Myr star cluster ISRF and Compiegne dust model. Light blue points: observed data with the errors, red squares: modelled broad-band fluxes, dashed-dot blue line: total (ionised and neutral) PAH emission, dashed-dot green line: VSG (SamC) grain emission, dashed-dot red line: BG (LamC and aSil grains) emission, and dashed purple line: NIR continuum.