Real-world emission characteristics of an ocean-going vessel through long sailing measurement

To quantify the emission characteristics of large ocean-going ships, onboard measurements were carried out for a large ocean-going vessel using portable emission measurement system (PEMS). The emission factors (EFs) of conventional pollutants and volatile organic compounds (VOCs) were greatly influenced by real-world operating conditions and engine loads. The sulfur dioxide (SO₂) and particulate matter (PM) emissions were mainly influenced by fuel type. The particle size distribution basically showed a single peak pattern, with nucleation mode particles as the main particles and the peak particle sizes ranging between 30 nm and 50 nm. The EFs for particle number (PN) ranged from 2.82 × 10¹⁶ to 4.49 × 10¹⁶ #/kwh. Carbonaceous components accounted for approximately 31.8% to 41.6% of the PM. SO₄^2-, NH₄⁺, Ca²⁺, Na⁺, and NO₃^- were dominant in water-soluble ions, while V and Ni were high-concentration metal elements, with the ratio of V: Ni ranging from 0.17 to 0.33. Increase in driving speed can lead to the increase in VOCs emissions. Our study presented a comprehensive test method with PEMS, which provides a reference for acquiring future real-world EFs. However, only one representative ship in China using a specific fuel was selected for the test, so it is important to characterize a broader range of ships and fuels.

On-board measurements of particle and gaseous emissions from a large cargo vessel at different operating conditions

This study investigated particle and gaseous emission factors from a large cargo vessel for her whole voyage including at berth, manoeuvring and cruising. Quantification of these factors assists in minimising the uncertainty in the current methods of exhaust gas emission factor estimation. Engine performance and emissions from the main marine engine were measured on-board while the ship was manoeuvring and cruising at sea. Emissions of an auxiliary engine working at 55% of maximum continuous rating (MCR) were measured when the ship was at actual harbour stopovers. Gaseous and particle emission factors in this study are presented in g kWh^-1 or # kWh^-1, and compared with previous studies. Results showed that the SO₂ emission factor is higher than that of previous studies due to the high sulphur content of the fuel used. The particle number size distributions showed only one mode for different operating conditions of the ship, with a peak at around 40-50 nm, which was dominated by ultrafine particles. Emission factors of CO, HC, PM and PN observed during ship manoeuvring were much higher than that of those recorded at cruising condition. These findings highlight the importance of quantification and monitoring ship emissions in close proximity to port areas, as they can have the highest impact on population exposure.