On-site measured emission factors of polycyclic aromatic hydrocarbons for different types of marine vessels

Abstract

A portable emission sampling system was used to perform on-site measurements of the emission factors (EFs; quantities of pollutants emitted per unit of energy consumed) of 29 polycyclic aromatic hydrocarbons (PAHs) for five types of marine vessels using light diesel in Hainan Province, China. Both gaseous- and particulate-phase PAHs from vessel emissions were sampled and measured using gas chromatography coupled with mass spectrometry (GC-MS), and the PAH EFs were calculated based on the carbon mass balance method. The average EFs of gaseous- and particulate-phase PAHs were 6.2 ± 7.8 and 17 ± 26 mg/kg, with naphthalene (NAP) and phenanthrene (PHE) dominating the gaseous- and particulate-phase PAH emissions, respectively. Among the five types of vessels, the EFs for small fishing boats were significantly higher than those for other types of vessels, and the lowest EFs were found for tug boats. Composition profiles and typical isomer ratios of PAHs were calculated for five types of vessels. Particulate-phase PAHs accounted for 63 ± 16% of the total emissions of 29 PAH species, and the particulate/gaseous-phase partitioning of PAHs was dominated by organic carbon (OC) absorption rather than black carbon (BC) adsorption. Emission factors of PAHs under different activity conditions were measured and calculated, and relatively higher EFs were found in the maneuvering mode for medium fishing boats and in the operating mode for engineering vessels. No significant differences were found among the PAH composition profiles under different activity conditions.