In Situ Collection and Photochemical Aging of Individual Ship Plumes Captured at Sea

Abstract Ship emissions contribute significantly to climate change and to air pollution at both global and regional scales. Considering the changes in physical and chemical properties as well as long-range spatial distribution of primary emissions during atmospheric aging, the implications for climate and public health remain poorly constrained. Real-world investigations of ship plume characteristics and their evolution remain very limited and often lack flexibility and/or transferability. We developed a new framework, applying an oxidation flow reactor aboard a mobile research vessel with aerosol analytical equipment. This pilot study in the Baltic Sea demonstrates the targeted analysis of individual ocean-going vessels. Specifically, gas phase and (potential) aerosol mass emission factors of real-world fresh ship plumes probed at distances of 0.6–1.6 km and of the research vessels’ own plume were determined. After photochemical aging, a notable increase in particle mass concentration was observed for all ships. Ships with higher emissions of SO2, and hence higher fuel sulfur content, showed larger aerosol formation potential which aligns with the well-established concept of sulfate as a driver of particle formation. Our study introduces the proof-of-concept for a scalable experimental framework joining and extending laboratory stack emission aging and stationary ambient monitoring.