Impact of shipping emissions on air pollution and pollutant deposition over the Barents Sea

Analysis of the uncertainty of the AIS-based bottom-up approach for estimating ship emissions

Although the AIS-based bottom-up approach has become the dominant method for estimating ship emissions, there are still inherent uncertainties due to the numerous complex factors involved. This paper aims to investigate the development process of the AIS-based bottom-up approach and identify the primary sources of uncertainty by conducting a systematic review of 29 articles published since 2015. The result shows three sources of uncertainty for estimating ship emissions, i.e., the acquisition and processing of AIS data, ship characteristic information and engine load calculation, and the determination of emission factors. This paper suggests that the accuracy of ship emission inventories can be improved by enhancing the reliability of datasets, uniformly defining engine load calculation formulas, and making more extensive measurements of local emissions to provide substantial support for ship emissions management and facilitate the development of more effective emission reduction strategies.

The impacts of ship emissions on ozone in eastern China

Tropospheric ozone (O3), which is one of the main pollutants impeding air quality compliance, has received considerable attention in China. As maritime transportation continues to expand, the effect of ship emissions on air quality is becoming increasingly important. In this study, the Weather Research and Forecast model (WRF), the Community Multiscale Air Quality model (CMAQ), and the integrated process rate (IPR) module provided in the CMAQ are applied to evaluate the impacts of ship emissions on O3 concentration at a national scale in China, including the spatiotemporal characteristics and influencing pathways. Ship emissions can increase or decrease O3 concentrations, with varying effects in different seasons and regions. In the winter, spring, and fall, ship emissions were predicted to decrease O3 concentrations in most areas, whereas in the summer, they increase the O3 concentration, even in regions far away from the coastline, thus adversely affecting the Yangtze River Delta (YRD) and Pearl River Delta (YRD). Additionally, owing to differences in the emissions of volatile organic compounds and nitrogen oxides, the northern and southern regions of the YRD respond differently to ship emissions. Additionally, the influence of ship emissions on the diurnal variation of O3 in the summer was investigated, where significant differences were indicated between cities. The IPR was used to investigate the individual processes contributing to changes in the O3 concentration caused by ship emissions. The transport process appears to be the primary contributor to O3 production, whereas chemistry and dry deposition played key roles in O3 loss. This study provides an in-depth insight into the impacts of ship emissions on O3 in China, which can facilitate the formulation of corresponding environmental policies.