To investigate the trends of chemical characteristics of precipitation in Taiyuan, and factors influencing their variations, a total of 350 precipitation samples were collected from April 2011 to November 2018. The principal water-soluble ions were measured by ion chromatography. PH value (4.34–8.72) was recorded and 14% of all samples were acidic, and was negatively correlated with rainfall amount. The frequency of acid rain decreased year by year, and the acidity was still dominated by SO₄²⁻. SO₄²⁻, Ca²⁺, NH₄⁺ and NO₃⁻ were the most abundant ions, accounting for 85% of the total concentration, with a significantly decrease rate of 61% during 8 years due to a series of emission reduction measures. The average ratio of neutralizing potential to acidifying potential was 1.37 and experienced an evident increasing trend. This was primarily ascribed to reduced input of SO₄²⁻ in precipitation. The precipitation acidity was predominantly neutralized by crustal ions Ca²⁺ and Mg²⁺. The ionic wet deposition flux was positively correlated to the rainfall amount. Based on Correlation analysis and Positive Matrix Factorization results, four pollution sources of coal combustion and vehicle mixing source (56%), dust (23%), agriculture and industry mixing source (16%) and biomass burning (5%) were identified. Back trajectory showed the air quality of Taiyuan was most significantly affected by the short-distance air mass from the southwest (40%). In order to achieve the SO₂ (47%) and NO_X (57%) emission reduction targets, we provided a specific energy reform plan in major cities affecting the air quality of Taiyuan before 2030.

为了调查太原市降水化学特征的变化趋势及其影响因素，从2011年4月至2018年11月共收集了350个降水样品。采用离子色谱法测定了主要的水溶性离子。记录的PH值（4.34-8.72），所有样品中有14％是酸性的，并且与降雨量呈负相关。酸雨的频率逐年下降，而酸度仍以SO ₄ ^2-为主导。SO ₄ ^2-，钙²⁺，NH ₄ ⁺和NO ₃ ^-是最丰富的离子，占总浓度的85％，并且由于采取了一系列减排措施，在8年中的下降速度达到61％。中和电位与酸化电位的平均比为1.37，并且呈现明显的增加趋势。这主要归因于降水中SO ₄ ^2-的输入减少。沉淀酸度主要被地壳离子Ca ²⁺和Mg ^2+中和。。离子湿沉降通量与降雨量呈正相关。根据相关分析和正矩阵分解结果，确定了四种污染源：燃煤和车辆混合源（56％），粉尘（23％），农业和工业混合源（16％）和生物质燃烧（5％）。倒退轨迹显示，太原的空气质量受西南短距离空气质量的影响最大（40％）。为了实现SO ₂（47％）和NO _X（57％）减排目标，我们在2030年之前针对影响太原市空气质量的主要城市提供了具体的能源改革计划。