AUTHOR=Wang Lizhi , Du Wei , Shen Huizhong , Chen Yuanchen , Zhu Xi , Yun Xiao , Shen Guofeng , Chen Yilin , Liu Junfeng , Wang Xuejun , Tao Shu 

TITLE=Unexpected Methane Emissions From Old Small Fishing Vessels in China

JOURNAL=Frontiers in Environmental Science

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/environmental-science/articles/10.3389/fenvs.2022.907868

DOI=10.3389/fenvs.2022.907868

ISSN=2296-665X

ABSTRACT=<p>Diesel-fueled ships have long been considered to contribute a marginal fraction of the global methane (CH<sub>4</sub>) emission budget compared to liquified natural gas (LNG)-fueled ships. Here, based on real-world measurements, we find that a specific yet-overlooked group of diesel-fueled ships–the old small fishing vessels (OSFVs)–is associated with high levels of CH<sub>4</sub> emissions. The emission factors of CH<sub>4</sub> from OSFVs is on average 5.2 ± 6.4 g CH<sub>4</sub> per 1 kg fuel consumed, approaching EF<sub>CH4</sub> of LNG-fueled ships (5.3–30.1 g/kg) and being at least six times EF<sub>CH4</sub> of other types of diesel-fueled ships (0.0–0.9 g/kg). We estimate that CH<sub>4</sub> emissions from OSFVs in China amount to 570–2,240 t per year, which is comparable to the total CH<sub>4</sub> emission from all LNG-fueled ships worldwide. Our results thus call for revision of the global CH<sub>4</sub> emission inventory for shipping.</p>