This Guide is to be applied to exhaust emission abatement systems fitted to ABS classed vessels primarily covering SOx scrubbers, SCR systems, Exhaust Gas Recirculation (EGR) arrangements, and to Exhaust Emissions Monitoring Systems (EEMS) associated with the aforementioned emission abatement systems, or EEMS installed as an alternative Onboard NOx Verification Procedure in accordance with the Direct Measurement and Monitoring Method of the NOx Technical Code.