关键词: 大气降水, PM_2.5, 能源结构, 化学组成

Abstract: During urban development, a large number of nitrogen and sulfur compounds are emitted into the atmosphere, posing severe challenges to the urban ecological environment. Exploring the relationship between the transformation of energy structure and the sources and controlling factors of atmospheric nitrogen and sulfur pollutants during urban development holds great significance for the rational planning and allocation of energy. In this study, atmospheric rainfall water samples and PM_2.5 samples in 2023 and historical precipitation and industry and agriculture related statistical data from Guiyang were collected to assess NH₄⁺, NO₃^-, SO₄^2- concentration and their ratios. The long-term variations in nitrogen and sulfur deposition, as well as their relationship with changes in energy structure were analyzed. The results showed that the deposition of nitrogen and sulfur at the monthly scale was affected by precipitation, coal combustion and agricultural activities, exhibiting obvious seasonal variations. Affected by the changes of precipitation, temperature and source emissions, the equivalent concentrations of NO₃^-, NH₄⁺, SO₄^2- in spring and winter precipitation and PM_2.5 increased significantly, and the concentrations were relatively low in summer and autumn. Compared with other cities in China, Guiyang had higher SO₄^2- emissions. From 1994 to 2023, the proportion of nitrate in atmospheric nitrogen deposition had an increasing trend, which increased the supply of nitrogen in the ecosystems of the study area, and had a certain potential impact on water bodies, forests and other systems. The change of energy structure, production and life had an important impact on nitrogen, sulfur and other air pollutants. The emission type of air pollutants gradually changed from the sulfuric acid type in the early stage to a mixed type, mainly because the energy structure has gradually changed from coal based to oil and power based. Such change in emission types has significant guiding significance for the rational planning and allocation of energy as well as the optimized use of fertilizers.

Key words: atmospheric precipitation, PM_2.5, energy structure, chemical composition