Left panel: emission-line ratio of [O iii]/Hβ as a function of [O iii] surface brightness for the original data after removing the broad Hβ line (black data points) and after performing the QSO-host galaxy deblending (red data points). The shaded area indicates the rms of line ratios within a given bin. The dashed line indicates the 3σ detect limit for Hβ for a given [O iii]/Hβ ratio given the estimated noise in the unblended data. Middle panel: line ratios as a function of distance D from the QSOs. Right panel: line ratio maps before and after the QSO-host galaxy deblending.