The alkalinity of the sea and harbours open to the sea is typically high and therefore suitable for exhaust gas cleaning. In fact many rivers also have a suitably high alkalinity.

It is not possible to carry out continuous online monitoring of alkalinity with sensors, but it could be checked by chemical titration, which is not entirely practicable onboard ship. Although there is no direct link between salinity and alkalinity or pH and alkalinity, online monitoring of the exhaust gas cleaning system’s water supply with pH and salinity sensors is used as a robust indicator of possible issues i.e. a low salinity and/or pH would suggest entry to brackish water.