Open Loop Scrubbers,Open-loop scrubbers reduce emissions using seawater. 

Open loop scrubbers are the most widely used type of marine exhaust cleaning system. They use seawater to wash sulfur oxides (SOx) out of ship exhaust gases, discharging the wash water back into the sea after treatment.

These systems are popular due to their lower installation and operational costs compared to closed-loop or hybrid alternatives. However, some ports and regions have restricted their use due to concerns over water quality and environmental impact.

Despite limitations, open loop scrubbers remain an attractive compliance solution for vessels operating mainly in international waters where regulations allow their use.