SOx What is the potential in reducing nitrogen and sulphur oxide on-board?

There is potential to reduce nitrogen and sulphur oxides from sea-going ships. Current technologies for NOx control are: Basic internal engine modification (IEM) which reduces by 20%, Direct Water Injection (DWI) reduces by 50%, Humid Air Motor (HAM) reduces by 70-85% and Selective Catalyst Reduction reduces by up to 99% emissions are relevant to the sulphur content of the fossil fuels. Marine gas oil and marine diesel oil have a maximum of 1,5-2 % m/m sulphur content, natural gas has almost zero (about 0,0015 g/kWh). Sea-water scrubbers can reduce sulphur emissions by 70-90%.