MSX and IRAS mid-IR and far-IR integrated photometry for 57 SF regions from Conti & Crowther (2004), supplemented by all published sub-mm and/or near-mm data for which integrated flux measurements covering the full angular extent of the source are available (18 sources); (see Table 1). Measurements are normalised to the 100 μm flux density. The solid line is the adopted model for the PDR dust, PAH emission from Groves et al. (2008), having compactness parameter log (C) = 6.5, metallicity 1.0, and PDR column density log (N) = 22.0. The dashed-line, which deviates slightly from the solid line in the submm range, is the same but with the free-free emission included.