Investigation on the effect of ship emissions on the air quality: A case study in Hainan Island, China

This paper presents an air quality simulation model that incorporates shipping activities and weather conditions, with a case study of Hainan Island to examine the impact of ship emissions on air quality. The findings reveal that the density of automatic identification system (AIS) signals is particularly high in the southern coastal regions. The results showed that the annual ship emissions recorded the highest density of 896.7 tons/0.01°, 49.8 tons/0.01°, 1139.7 tons/0.01°, and 122,000 tons/0.01° for sulfur oxides (SO_x), particulate matter (PM), nitrogen oxides (NO_x), and carbon dioxide (CO₂), respectively. Furthermore, the partial distributions of these emissions were not significantly affected by the seasons. Ships within twelve nautical miles of Hainan coastlines emit approximately 2817.7 tons of SO_x, 14,686.4 tons of NO_x, 630.4 tons of PM_2.5, and 416.9 tons of hydrocarbons (HC) annually. These emissions are primarily concentrated in the sea areas surrounding the ports of Haikou, Yangpu, Basuo, and Sanya. Ships manufactured between 2000 and 2010 have contributed significantly to air pollution, with SO_x and HC emissions accounting for approximately 51 % and 56 % of total emissions, respectively. However, for ships manufactured after 2016, these proportions have dropped to approximately 10 %. In terms of air pollutants from ship emissions in Hainan Island, the spatial distribution of their contributions is significantly uneven. The impact of PM_2.5 differs significantly depending on the season, with the concentrations being substantially higher during Spring. However, the proportions of O₃ and other pollutants do not vary significantly, except during Spring.