Alastuey A, Querol X, Chaves A, Ruiz C R, Carratala A, Lopez-Soler A
Institute of Earth Sciences Jaume Almera, CSIC, C/ Lluis Solé Sabarís, s/n, 08028 Barcelona, Spain.
Environ Pollut. 1999 Sep;106(3):359-67. doi: 10.1016/s0269-7491(99)00103-7.
This work focuses on bulk deposition in a rural area located around a large coal-fired power station in northeast Spain. Deposition chemistry was characterised by high concentrations of SO(4)(2-), Ca(2+) and NH(4)(+), which were relatively high when compared with other rural areas. Monthly bulk deposition evolution of major ions was the result of two superimposed patterns: one pattern related to the volume of precipitation and the other showed the seasonal influence of the major ionic sources. A major local origin was attributed to bulk deposition of SO(4)(2-), NH(4)(+), and Ca(2+), whereas a relatively higher contribution of an external source was deduced for NO(3)(-), Na(+) and Cl(-). The SO(4)(2-) concentrations showed a significant correlation with the local SO(2) emissions. High levels of Ca(2+) were due to the high alkalinity of soils in the study area, although an external origin was attributed to the frequent air mass intrusions from the Sahara. Sources of NH(4)(+) were related to intensive livestock farming in the area. Total suspended particles exert a marked influence over bulk deposition and neutralisation. Thus, despite the high emissions of SO(2) in the area, neutral pH values have always been attained given that the concentrations of Ca(2+) and NH(4)(+) account for the total neutralisation of NO(3)(-) and SO(4)(2-).
这项工作聚焦于西班牙东北部一座大型燃煤发电站周边农村地区的大气湿沉降。沉降化学特征表现为硫酸根离子（SO₄²⁻）、钙离子（Ca²⁺）和铵根离子（NH₄⁺）浓度较高，与其他农村地区相比相对较高。主要离子的月度大气湿沉降变化是两种叠加模式的结果：一种模式与降水量有关，另一种则显示了主要离子源的季节影响。硫酸根离子（SO₄²⁻）、铵根离子（NH₄⁺）和钙离子（Ca²⁺）的大气湿沉降主要源自本地，而硝酸根离子（NO₃⁻）、钠离子（Na⁺）和氯离子（Cl⁻）则推断有相对较高的外部来源贡献。硫酸根离子（SO₄²⁻）浓度与当地二氧化硫排放显著相关。钙离子（Ca²⁺）含量高是由于研究区域土壤碱度高，不过也有外部来源，即撒哈拉地区频繁的气团入侵。铵根离子（NH₄⁺）的来源与该地区密集的畜牧业有关。总悬浮颗粒物对大气湿沉降和中和作用有显著影响。因此，尽管该地区二氧化硫排放量高，但鉴于钙离子（Ca²⁺）和铵根离子（NH₄⁺）的浓度中和了硝酸根离子（NO₃⁻）和硫酸根离子（SO₄²⁻），始终能达到中性pH值。
