Air pollution from ships has a significant impact on both public health and climate, affecting the entire atmospheric environment. To address this issue, emission control areas (ECA) have been established. In ECAs, traditional bunker fuels are replaced by distillates such as marine gas oil, or ships are equipped with exhaust gas cleaning devices 'scrubbers' to reduce sulphur emissions. The use of cleaner fuels still has serious health effects, but they do not contain metal residues from the refining process. Therefore, the conventional marker concept for ship emissions is no longer applicable. To address this issue, we propose a novel approach for identifying ship emission particles based on their polycyclic aromatic hydrocarbon content (PAH). Through the use of new ionization methods in single-particle mass spectrometry (SPMS, Schade et al., 2019), we were able to obtain PAH mass spectra from individual particles emitted by a ship engine running on various fuels. Our findings indicate that there are fuel-specific signatures for the majority of particles (Anders et al., 2023). These PAH fingerprints are stable for different engine loads and particle sizes, indicating the fuels used, regardless of the metals present. We show that our approach can detect ship emissions in the atmosphere in real time, even in ECA regions where the majority of ships run on marine gas oil. For such ships, we were able to detect individual plumes over distances of more than 10 km based on the presence of characteristic PAH fingerprints. To identify ships running on bunker fuels, we combined the above method with resonant ionization of the metals in their fuel emissions, as described by Passig et al. (2020). This improvement allows the detection of particles from ships with scrubbers (Passig et al., 2021) from distances up to 15 km, including in urban environments. With our technique, compliance checks for allowed fuels on the open sea can be effective over distances of several kilometres (Rosewig et al., 2023). This work was supported by the Helmholtz Association (International Laboratory aeroHEALTH – Interlabs-0005), the Deutsche Forschungsgemeinschaft (grant no. ZI 764/6-1) and the German Federal Ministry for Economic Affairs and Climate Action (grant nos. 03SX483D, ZF4402101ZG7 and 16KN083626).    «

Air pollution from ships has a significant impact on both public health and climate, affecting the entire atmospheric environment. To address this issue, emission control areas (ECA) have been established. In ECAs, traditional bunker fuels are replaced by distillates such as marine gas oil, or ships are equipped with exhaust gas cleaning devices 'scrubbers' to reduce sulphur emissions. The use of cleaner fuels still has serious health effects, but they do not contain metal residues from the refi...    »