Article: The impact of port throughput and throughput growth on sulphur-oxide concentrations in China's coastal ports: boosters or brakes Journal: International Journal of Shipping and Transport Logistics (IJSTL) 2026 Vol.22 No.4 pp.525 - 544 Abstract: This study investigates how port throughput scale and throughput growth relate to sulphur-oxides (SOX) concentrations at 18 major coastal ports in China. Using a port-year panel dataset over 2005-2019 and combining satellite-based SOX observations with a consistent set of port operational indicators, we apply quantile regression to examine nonlinearities and distributional heterogeneity. The results suggest an EKC-type pattern in which expanding throughput can increase SOX in earlier stages, whereas further expansion can coincide with reduced SOX as ports modernise and compliance capacity strengthens. We also document pronounced regional and scale heterogeneity: northern and eastern ports exhibit an inverted-U relationship between throughput and SOX, while southern ports show a U-shaped pattern. Overall, high-throughput ports tend to exert stronger impacts on SOX outcomes, underscoring the role of operational intensity. These findings imply that mitigation policies should be tailored to port-specific characteristics, including development stage, scale and regional context. Inderscience Publishers - linking academia, business and industry through research

Title: The impact of port throughput and throughput growth on sulphur-oxide concentrations in China's coastal ports: boosters or brakes

Authors: Jihong Chen; Yejun Liu; Lang Xu; Chengkun Liu; Yusheng Zhou

Addresses: College of Transport & Communications, Shanghai Maritime University, Shanghai, China ' College of Transport & Communications, Shanghai Maritime University, Shanghai, China ' College of Transport & Communications, Shanghai Maritime University, Shanghai, China ' Institute for Sustainable Development, Macau University of Science & Technology, Macau ' Department of Logistics & Maritime Studies, The Hong Kong Polytechnic University, Hong Kong

Abstract: This study investigates how port throughput scale and throughput growth relate to sulphur-oxides (SO_X) concentrations at 18 major coastal ports in China. Using a port-year panel dataset over 2005-2019 and combining satellite-based SO_X observations with a consistent set of port operational indicators, we apply quantile regression to examine nonlinearities and distributional heterogeneity. The results suggest an EKC-type pattern in which expanding throughput can increase SO_X in earlier stages, whereas further expansion can coincide with reduced SO_X as ports modernise and compliance capacity strengthens. We also document pronounced regional and scale heterogeneity: northern and eastern ports exhibit an inverted-U relationship between throughput and SO_X, while southern ports show a U-shaped pattern. Overall, high-throughput ports tend to exert stronger impacts on SO_X outcomes, underscoring the role of operational intensity. These findings imply that mitigation policies should be tailored to port-specific characteristics, including development stage, scale and regional context.

Keywords: coastal port; environmental Kuznets curve; EKC; sulphur-oxide concentration; quantile regression; throughput growth; China.

DOI: 10.1504/IJSTL.2026.154264

International Journal of Shipping and Transport Logistics, 2026 Vol.22 No.4, pp.525 - 544

Received: 11 Jul 2025
Accepted: 23 Dec 2025
Published online: 18 Jun 2026 *

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Title: The impact of port throughput and throughput growth on sulphur-oxide concentrations in China's coastal ports: boosters or brakes

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