High PM(2.5 )Emission from Typical Old, Small Fishing Vessels in China

Old, small fishing vessels (OSFVs) account for a considerable proportion of the fishing fleet in China, the world's top fishery country. Exhaust from OSFVs is often poorly controlled, but because of a lack of measurements, the magnitudes of OSFVs' emissions in China remain unclear. In this study, we measured real-world PM2.5 emission factors (EFs) from three typical OSFVs, together with other commonly used offshore vessels, in Hainan, China. The average PM2.5 EF for OSFVs is 71.7 (37.3-92.7) g.(kg fuel)(-1), which is 4-10 times greater than the average of other types of vessels and an order of magnitude greater than commonly adopted shipping EFs in the literature. Annual PM(2.5 )emission from OSFVs was estimated to be 2.13 (1.18-2.86) kt in Hainan in 2017, comparable to the level of on-road mobile emission there. Our results show that OSFVs are possibly a group of "super-emitters" among marine vessels, which are underrepresented in the shipping emission inventories. Prioritizing regulations for OSFVs is a viable option to mitigate ambient PM2.5 pollution in Hainan as well as in other coastal regions with active small-scale fisheries in low-income communities.