Abstract: Based on long-term observations of precipitation from 2006 to 2024 in Wuhua District,the central urban area of Kunming,this study analyzed the interannual and monthly variations in pH,electrical conductivity,and chemical composition of atmospheric precipitation.The potential sources of chemical components were investigated through enrichment factors (EF),characteristic ion ratios,and Positive Matrix Factorization (PMF) model.The results showed that the mean pH of precipitation in Wuhua District was 6.58 with a significant increasing trend,while the average electrical conductivity was 27.6 μS/cm,showing a pattern of "higher in the dry seasons and lower in the wet seasons" on a quarterly basis.The average concentration of anions and cations in precipitation was 303.6 μeq/L,with the order of contribution being Ca²⁺ > SO₄^2- > NH₄⁺ > NO₃^- > Mg²⁺ > Cl^- > Na⁺ > K⁺ > F^-.The dominant cations were Ca²⁺ and NH₄⁺,while the primary anions were SO₄^2- and NO₃^-.Combined analysis using EF,characteristic ion ratios,and PMF model,the water-soluble ionic components in precipitation were primarily derived from five sources:mobile sources (27.5%),agricultural activities and biomass burning (22.0%),marine sources (6.1%),soil dust (12.6%),and industrial emissions (31.8%).These findings provide scientific references for understanding the status and trends of atmospheric environmental quality in Kunming and formulating air pollution control strategies in plateau regions.