The EC90 was considered the optimal SO2 Ct product because its value was >400 (L L−1) h for the SO2 streams of 22.5 or 101.6 L L−1 instead of 320 (L L−1) h, which was produced with 50.2 L L−1 for ‘Brigitta’, or >400, 245 and 252 (L L−1) h,
which were produced for ‘Liberty’ when the SO2 streams were 22.5, 50.2 and 101.6 L L−1, respectively