Radial trends of SNRs and H II regions. r/r_eff is the ratio of SNR distance to the effective radius of the corresponding galaxy. Panel (a): [S II]/Hα changes with the distance to their corresponding galactic centers for SNRs (red dots) and H II regions (in grayscale). Panel (b): [N II]λ6583/Hα change with the distance to their corresponding galactic centers for SNRs (red dots) and H II regions (in grayscale). For SNRs that overlap with a H II region, the symbol is an empty circle in light red. The drop in the numbers at low r/r_eff is likely influenced by the mask in the centers of the galaxies.