Abstract
This research used the calculating method of dry deposition to estimate SO2 dry deposition value and evaluate its trend in 5 recent years. The results indicate that SO2 emission at Northern sites is more changing than Southern ones in months by affecting meteorology and weather. Summer and autumn seasons have SO2 emitted concentrations higher than other seasons in 2019, 2020, and 2022 year at Yen Bai, Hoa Binh, and Ha Noi stations. The 2021 year has the highest SO2 dry deposition and the 2019 year has the lowest SO2 dry deposition in 5 recent years. The Hanoi site has the highest SO2 dry deposition value from 2019 to 2022 year. Hoa Binh site has the highest SO2 dry deposition at 2.45 kg/ha/year in 2023. High SO2 dry deposition occurs normally in the summer and autumn (from April to August). Southern sites have lower SO2 dry deposition amounts with not much change than the Northern sites of Vietnam. The increasing trend of SO2 dry deposition happened from 1999 to 2023 year and it increases sharply from 1999 to 2021. Therefore, SO2 dry deposition will have a light-increasing trend in the future.
