We have performed a comparison between the molecular gas emission and the mid IR dust component emission distributions in a sample of nearby galaxies. We have compared CO maps at high spatial resolution, from Wilson et al. (2000), Bayet et al. (2004, 2006) and from Kramer et al. (2005), with the emission distributions of ionised and neutral PAHs (PAH+; PAH0) and of very small grains (VSGs), obtained using signal processing methods as explained in Berné et al. (2007a) and Rapacioli et al. (2005).In M 82, we have also compared the dust emission maps with dense gas tracer maps (HCO and H13CO+ data from García-Burillo et al. 2002) as well as with shock tracer maps (SiO data from García-Burillo et al. 2001).