[O iii]/24 µm for different models as a function of burst age. Each model is represented with a color for n0, and a line style for U, and the lines are following the proportion of PDR emission, c_PDR, with the markers representing the c_PDR of 0%, 50 % and 99%. The blue solid horizontal line corresponds to the median of the spatially resolved observations and the dashed blue lines to the median absolute deviation. The distribution of our observations is shown on the right as a histogram.