Gas-to-dust ratios for the four AGN populations, expressed as log(N_H/E(B − V)_AGN) (top panel) and log(N_H/A_V^ISM) (bottom panel). Whiskers extend to 1.5 × IQR, and individual points beyond this range are shown as single circles. Populations with only one available measurement (e.g. BLAbs at z < 0.4) are shown as single points to indicate the lack of statistical constraints. Median values and IQRs for different redshift intervals are presented in Table 4.