Integrated (0.4–10 GeV) γ-ray emmissivity per gas nucleon as a function of height above the Galactic plane. The black data points are from this study, the dark grey points from nearby anticentre clouds (Remy et al. 2017) and the light grey ones fromhigh-latitude clouds (adapted from Tibaldo et al. 2015, see text). The grey band gives the ± 1σ dispersion around the mean emissivity found at low Galactic height (≤300 pc). The dotted curve shows the best fit for pure CR diffusion and advection with Galactic height (see text). The dash-dotted curve corresponds to the distribution of 10 GeV protons in the halo model of Evoli et al. (2018), rescaled to the q_LIS emissivity at low Galactic height.