Measurements of air pollution emission factors for marine transportation in SECA

Abstract

The chemical composition of the plumes of seagoing ships was investigated during a two weeks long measurement campaign in the port of Rotterdam, Hoek van Holland, The Netherlands, in September 2009. Altogether, 497 ships were monitored and a statistical evaluation of emission factors (g kg-1 fuel) was provided. The concerned main atmospheric components were SO2, NO2, NOX and the aerosol particle number. In addition, the elemental and water-soluble ionic composition of the emitted particulate matter was measured. Emission factors were expressed as a function of ship type, power and crankshaft rotational speed. The average SO2 emission factor was found to be roughly half of what is allowed in sulphur emission control areas (16 34 vs. 30 g kg-1 fuel), and exceedances of this limit were rarely registered. A significant linear relationship was observed between the SO2 and particle number emission factor. The slope of the regression line, 2x1018 (kg fuel)-1, provides the average number of sulphate particles from 1 kg sulphur burnt with the fuel, while the intercept, 0.5x1016 (kg fuel)-1, gives the average number of primary particles (mainly soot and ash) formed during the burning of 1 kg fuel. Water-soluble ionic composition analysis of the aerosol samples from the plumes showed that approx. 144 g of sulphate particles were emitted from 1 kg sulphur burnt with the fuel. The mass median diameter of sulphate particles estimated from the measurements was 42 nm.