The comparison of the calculated amplification coefficients β_n,n+1 using the EPA model and the current model with full radiative transfer is plotted in the top panel. The corresponding comparisons of the β_n,n+1 in the center and boundary of H II regions, and the line luminosities are shown in the middle and bottom panels, respectively. The electron temperature, density and EM are 10000 K, 10⁷ cm^–3, and 6 × 10¹¹ cm^–6 pc, respectively. The σ_υ is 0 km s^–1 and 20 km s^–1 in the two cases.