Environmental significance of sulfur wet deposition in ecological barrier region, Qinghai-Tibet Plateau

Abstract

The Qilian Mountains are a significant ecological barrier in China. but the research on the characteristics of atmospheric Sulfur(S) wet deposition and the analysis of potential sources of SO₂ in this region are not adequate. In the study, 1382 samples of precipitation from 27 stations in the Qilian Mountains were analyzed. We quantified the wet deposition of atmospheric S on the Qilian Mountains, and the following conclusions were drawn. The annual average S wet deposition flux in the Qilian Mountains is 37.59 kg/hm². Due to the influence of precipitation patterns, the distribution of S wet deposition flux is uneven throughout the year, with 78.75 % of the total deposition occurring between May and October. Also, the S wet deposition flux shows an obvious spatial variability, with an increasing variation characteristic trend from west to east. Additionally, altitude, meteorological factors, and ecosystem types influenced the S wet deposition. The main sources and mechanisms of individual air pollutants in the Qilian Mountains are highly complex. The concentrations of SO₂ are strongly influenced by the regional transport of emissions, mainly from severe pollution source regions in South Asia, Western China, and Central Asia. It is recommended to reduce SO₂ emissions and protect ecological quality through industrial reforms, energy optimization, clean heating, land use adjustments, and ecological projects to improve public well-being.