The local effective emissivity ℰ_eff of the ISM per hydrogen atom recently measured (Abdo et al. 2009b) by the Fermi collaboration. The black data points are plotted with various predictions based on different γ-ray production cross sections. The red solid curve features our reference model for which the Huang et al. (2007) cross sections are combined with the Shikaze et al. (2007) proton and helium fluxes. The magenta short-dashed curve is the emissivity for only proton-proton interactions and is based on the Kamae et al. (2006) parameterization. Taking then into account the nuclear weight factors of Eqs. (28) and (27) yields the blue and orange long-dashed curves. In all cases, the cross sections are convoluted with the CR proton and helium fluxes measured at the Earth’s position by Shikaze et al. (2007).