Posted: January 24th, 2024
Seagoing ship emissions at Chinese coastal port cities and countermeasures analysis
Seagoing ship emissions at Chinese coastal port cities and countermeasures analysis
Seagoing ships are an important source of air pollution in China, especially in the coastal port cities where they dock and operate. According to a study by Sun (2015), seagoing ship emissions accounted for 8.4% of the total SO2, 11.8% of the total NOx, and 12.7% of the total PM emissions in Shanghai Port in 2013. These emissions not only affect the local air quality, but also contribute to regional haze and acid rain problems.
In order to reduce the environmental impact of seagoing ship emissions, China has implemented a series of domestic emission control area (DECA) policies since 2016, which require ships to use low-sulfur fuel oil or install emission abatement devices when entering the designated areas. The DECA policies have been gradually expanded and tightened over the years, covering most of the coastal areas and inland rivers of China by 2019.
A recent study by Wang et al. (2021) evaluated the effectiveness of the DECA policies on seagoing ship emissions around China from 2016 to 2019, based on a high-spatiotemporal ship emission inventory model that used automatic identification system (AIS) data and ship technical specifications. The results showed that SO2 and PM emissions from seagoing ships decreased by 29.6% and 26.4%, respectively, while NOx emissions increased by 13.0%. The most significant emission reduction was achieved in 2019, when the DECA 2.0 policy came into effect, which required ships to use fuel oil with a sulfur content of no more than 0.5% in the coastal areas within 12 nautical miles from the baseline. The study also found that containers and bulk carriers were the dominant contributors to seagoing ship emissions, and that some ships detoured outside the scope of DECA 2.0 to avoid using more expensive low-sulfur oil.
Another study by Li et al. (2020) measured the gaseous emissions from a seagoing ship under different operating conditions in the coastal region of China, using a portable emission measurement system (PEMS). The study compared the emissions from using marine gas oil (MGO) with a sulfur content of 0.1% and very low sulfur fuel oil (VLSFO) with a sulfur content of 0.5%, which are compliant with the DECA policies. The results showed that using VLSFO reduced the SO2 emissions by 81.4%, but increased the NOx emissions by 7.7%, compared to using MGO. The study also found that the emission factors of CO, HC, NOx, and SO2 varied significantly with different engine loads and operating modes.
These studies suggest that the DECA policies have been effective in reducing seagoing ship emissions of SO2 and PM in China, but have also led to some trade-offs and challenges, such as increased NOx emissions, fuel switching costs, and compliance issues. Therefore, more comprehensive and coordinated countermeasures are needed to further mitigate the environmental impact of seagoing ship emissions in China, such as promoting alternative fuels, enhancing emission monitoring and enforcement, and strengthening regional cooperation.
Works Cited
Li, Y., Lv, Z., Liu, H., He, K., Zheng, S., Wang, X., Yi, W., & Xu, H. (2020). Gaseous Emissions from a Seagoing Ship under Different Operating Conditions in the Coastal Region of China. Energies, 13(7), 1584. https://doi.org/10.3390/en13071584
Sun, J. (2015). Seagoing ship emissions at Chinese coastal port cities and countermeasures analysis: sample of Shanghai Port (Master’s thesis). World Maritime University. https://commons.wmu.se/msem_dissertations/88/
Wang, X., Yi, W., Lv, Z., Deng, F., Zheng, S., Xu, H., Zhao, J., Liu, H., & He, K. (2021). Ship emissions around China under gradually promoted control policies from 2016 to 2019. Atmospheric Chemistry and Physics, 21(18), 13835–13853. https://doi.org/10.5194/acp-21-13835-2021