On-board measurements of OC/EC ratio, mixing state, and light absorption of ship-emitted particles

Wenqi Hou; Zeyu Liu; Guangyuan Yu; Shujun Bie; Yan Zhang; Yingjun Chen; Dong Ma; Fan Zhang; Chunjing Lou; Xiaodong Hu; Yong Gui; Weizhong Zhou

doi:10.1016/j.scitotenv.2023.166692

On-board measurements of OC/EC ratio, mixing state, and light absorption of ship-emitted particles

Sci Total Environ. 2023 Dec 15:904:166692. doi: 10.1016/j.scitotenv.2023.166692. Epub 2023 Sep 1.

Authors

Wenqi Hou¹, Zeyu Liu¹, Guangyuan Yu¹, Shujun Bie¹, Yan Zhang², Yingjun Chen³, Dong Ma⁴, Fan Zhang⁵, Chunjing Lou⁶, Xiaodong Hu⁶, Yong Gui⁷, Weizhong Zhou⁸

Affiliations

¹ Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
² Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China; Shanghai Institute of Eco-Chongming (SIEC), Shanghai 200062, China. Electronic address: yan_zhang@fudan.edu.cn.
³ Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China. Electronic address: yjchenfd@fudan.edu.cn.
⁴ State Environmental Protection Key Laboratory of Vehicle Emission Control and Simulation, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
⁵ East China Normal University, Shanghai 200062, China.
⁶ Shanghai Waigaoqiao Shipbuilding Co., Ltd., Shanghai 200137, China.
⁷ CSSC Power (Group) Co., Ltd., Shanghai 200120, China; China Shipbuilding Power Engineering Institute Co., Ltd., CSSC Power (Group) Co., Ltd., Shanghai, 200120, China.
⁸ CSSC Power (Group) Co., Ltd., Shanghai 200120, China.

PMID: 37659551
DOI: 10.1016/j.scitotenv.2023.166692

Abstract

Carbonaceous aerosols play important roles in environmental impacts and climate effects. The characteristics of ship-emitted carbonaceous aerosols keep unclear under the latest global low sulfur fuel oil policy. This study selected four ocean-going vessels burning low sulfur fuel oils for on-board exhaust testing. The emission factors of ship carbonaceous aerosols were obtained under different engine types (main and auxiliary engines), fuel types, and engine loads. Our results showed that fuel and engine types were both important factors affecting carbonaceous aerosol emissions for ship engines. The emission factors of OC and EC from main engines were 1.18 ± 0.62 and 0.06 ± 0.04 g/kg burning heavy fuel oil (HFO), while 0.52 ± 0.35 and 0.04 ± 0.03 g/kg burning marine gas oil (MGO), respectively. The OC/EC ratios of ship-emitted particles were within a large range of 2 to 23. The OC/EC ratios from the main engines were significantly higher than those from the auxiliary engines by a factor of 6.3. The result of chemical mixing states of ship-emitted particles observed by a single particle mass spectrometer (SPAMS) showed that OC and EC were internally mixed and existed as the ECOC-bonded forms in single particles. The measured light absorption of ship-emitted particles with higher OC/EC ratios showed an evident short-wave absorption enhancement based on the aethalometer AE-33. Our results implied that ship-emitted carbonaceous aerosols (especially with high OC/EC ratios) could not be uniformly treated regarding the optical properties to more precisely estimate their potential environmental impacts and climate effects in model systems in the future.

Keywords: Carbonaceous aerosol; Light absorption; OC/EC; Ship emissions; Single particle.