Ratio of two tracers of PAH mass fraction (R_PAH and R_PAH^*) for ∼12000 H II regions from 19 PHANGS galaxies (top row) depending on R_PAH (left panel) and monochromatic luminosity L_ν(F770W_ss) (right panel). Cyan and black denote regions with hydrogen ionizing photons rate Q⁰ > 10⁵⁰ s⁻¹ and Q⁰ < 10⁵⁰ s⁻¹, respectively. R_PAH^* and R_PAH are consistent with each other for most of the regions, but R_PAH^* systematically overestimates PAH fraction for the luminous H II regions. The bottom row demonstrates the same ratio with R_PAH^* calculated after applying correction described in the text.