Redshift distribution of the intrinsic [O III] λ5007 line FWHM, resulting from the line-fitting procedure and subtracting the instrumental FWHM. On the left, we also report the median values of the FWHM of NLAGN (magenta), non-AGN (cyan) and of the global population (black) in five different redshift bins. Errors are derived using a bootstrap procedure. There is no significant trend of the FWHM of the sources with redshift. On the right, we report the histogram of the NL-FWHM distribution for AGN (red) and non-AGN (blue).