Fig. 4 is a parity plot of the meas

Fig. 4 is a parity plot of the measured versus model calculated
CO2 partial pressure data for PZ. As in the other cases no systematic
deviations are apparent. In the work of (Kamps et al., 2003)
and (Ermatchkov et al., 2006) the data was modelled using chemical
reactions equivalent to those used in this work. Activity coefficients
were calculated using modified Pitzer equations. Due to a lack of
information it is not possible to compare the AARD% from this
work to the literature results. However, it is worth noting that in
(Ermatchkov et al., 2006) when the interaction parameters were set
to zero (in which case the activity coefficient equations collapsed to
a system equivalent to Debye–Hückel) there was a negligible effect
on the result.