We measure and monitor Nitrogen Oxide (NOx), Sulphur Oxides (SOx), Particular Matter (PM), Volatile Organic Compounds (VOC) and Black Carbon. Their emissions are generally proportionate to our use of fuel and the reasons for fluctuations are identical to those for Scope 1 and Scope 3 fuel consumptions.
*Note: "Black Carbon (BC) data is currently a best approximation as it depends non-linearly on the engine load, which obviously varies over the operational cycle of a ship and the fuel properties, with an interesting observation that Light Fuel Oil (LFO) may not have the expected benefits when compared with some Heavy Fuel Oils (HFO). CIMAC concluded that use of distillate fuel (MGO) may not result in reduced black carbon emissions compared to HFO usage in larger engines.
In research to date, measurements of ship-related BC emission factors have ranged from 0.1 to 1 g/kg fuel, but the exact contribution is a matter needing further research given the span of results. We have used three conversion figures for SPO's fleet, recognising the variation in engine load cycles among those on PSVs, those on AHTS Vessels and a generic factor for other types of vessels."
For further information:
Black Carbon Measurement Methods and Emission Factors from Ships
Water Use - Not Material