Three-Dimensional Spatial Distribution of the Sedimentation Rate of Chloride Ions on a Tropical Island

Chlorine ions in the air are a key factor in the corrosion of offshore buildings. Mastering the distribution law of the chloride ion settlement rate (RCl-) in three-dimensional (3D) spatiality is helpful in protecting offshore buildings. The self-designed “kite-hanging wet candle method” was used to collect chloride ions in the air, using ion chromatography to analyze the chloride ion concentration of the sample solution, and obtained the annual RCl- in the offshore atmosphere at different vertical heights, using the Pearson correlation coefficient method to analyze the influence of environmental factors on the RCl-. The results show that the RCl-has a significant linear relationship with temperature, relative humidity and wind speed. Among them, the RCl- is positively correlated with temperature and negatively correlated with wind speed and relative humidity. In the vertical height range of 10–100 m, the RCl- presents a “⊂”-shaped distribution. In the range of 10–30 m, the RCl- is mainly controlled by the impact of ocean spray; in the range of 30–80 m, the RCl- is mainly controlled by marine aerosols; and in the range of 80 m–100 m, the RCl- is mainly controlled by marine aerosols and wind speed. Under the influence of wind direction and wind speed, the RCl- of the windward side is higher than that of the leeward side at different monitoring points, which are close to the coastline and at a low vertical height. Studying the distribution of the RCl- in 3D spatiality can effectively prevent and reduce its impact on offshore buildings.