Particulate matter from ship exhaust

Particulate matter from marine combustion is the fraction of the exhaust that exists as solid or liquid aerosol rather than gas: sulphate and associated bound water, elemental and organic carbon, ash and metals. MARPOL Annex VI regulates it indirectly. Regulation 14 is titled Sulphur Oxides and Particulate Matter, and the emission control areas designated under it are SOx and particulate matter ECAs, but the operative limit in every case is a fuel sulphur limit.

That drafting choice has a direct consequence for abatement. Because the sulphate fraction scales with fuel sulphur, cutting sulphur cuts PM, and an exhaust gas cleaning system accepted as equivalent on the sulphur limit satisfies the particulate matter element of the designation by the same route. What the instrument does not do is set a PM mass limit that could be measured directly.

The full article will cover PM formation and composition, the difference between filterable and condensable fractions, measurement methods and their disagreement, black carbon and the unfinished work at the Sub-Committee on Pollution Prevention and Response, and the health impact literature that drove the ECA designations.