Cost-benefit analysis of ships NOx Emission Control Areas (NECA) along China's coastal area

Shipping, as a crucial pillar of global trade, generates significant amounts of nitrogen oxides (NO_x), which profoundly impact the environment and public health. As a major global shipping nation, China faces severe challenges in NO_x emissions reduction. This study constructs a bottom-up emission inventory model using Automatic Identification System (AIS) data and vessel profile databases to evaluate the feasibility and cost-effectiveness of implementing NO_x Emission Control Areas (NECA) along the Chinese coastline. The results indicate that implementing NECA within 12 nautical miles, 50 nautical miles, and 100 nautical miles reduces NO_x emissions by 8.3 %, 12.5 %, and 13.4 %, respectively. Among these, the 100-nautical-mile range achieves the most significant reduction, with a 48.8 % decrease in NO_x emissions specifically from ships built after 2016. Among different emission reduction technologies, Selective Catalytic Reduction (SCR) proves to be more cost-effective and efficient than Exhaust Gas Recirculation combined with Water Injection (EGR + WIF) for long-distance voyages. In contrast, EGR + WIF demonstrates better economic performance in short-distance voyages and low-load conditions. Cost-benefit analysis reveals that expanding the NECA range to 50 and 100 nautical miles results in cost-benefit ratios of 2.93 and 3.86, respectively, confirming the significant economic and health benefits of this policy in larger areas. Despite high initial costs, the substantial long-term environmental and public health benefits justify the widespread implementation of NECA along China's coastline.