This work investigates the spatial and temporal variability of atmospheric ammonia concentrations in the Lombardy region in Northern Italy, where its continuous measurement at hourly resolution began in 2007 at monitoring sites representative of three different land use areas (urban, rural, and mountain locations). Ammonia concentration data have been jointly analyzed with wind direction and speed to highlight the association between the origin of the air masses and the concentration levels observed at the monitoring sites far from the primary sources, essentially consisting of farming activities and cattle and pigs breeding located in the southeastern part of the Lombardy region. The annual average concentrations of ammonia observed at urban (4.4–13.4 μg m⁻³ range) and rural (17–35 μg m⁻³ range) monitoring sites are in substantial agreement with literature data, which are however limited and strongly influenced by the measurement techniques used. The lowest concentration levels (1.1–5.8 μg m⁻³ range) are observed at the monitoring sites in the mountain areas. Both the seasonal and daily time patterns of the concentrations appear strongly related to some features of the measurement sites, namely with regard to their exposure to agricultural activities, whose seasonal practices arise in emissions responsible for strong variations in the ammonia atmospheric levels. Conversely, in the mountain areas in the north of region, local conditions affecting the atmospheric circulation seem to play a more important role than local sources, with the highest concentrations occurring when the breezes transport NH₃-rich air masses from the southern part of the region.

这项工作调查了意大利北部伦巴第地区大气氨浓度的时空变化，该区域以小时分辨率连续测量于2007年在代表三个不同土地利用区域（城市，农村和山区）的监测点开始。氨气浓度数据已与风向和风速进行了联合分析，以突显空气质量的起源与在远离主要来源的监测地点观察到的浓度水平之间的关联，这些浓度主要包括农业活动以及位于该州的牛和猪的繁殖伦巴第大区的东南部。平均浓度的氨在城市（4.4-13.4微克米观察到^-3的范围）和农村（17-35微克米^-3范围）的监测点与文献数据基本一致，但是受到了限制，并且受到所用测量技术的强烈影响。最低浓度水平（1.1–5.8μgm ^-3范围）在山区的监测点观察到。浓度的季节性和每日时间模式似乎都与测量地点的某些特征密切相关，即与它们暴露于农业活动有关，这些活动的季节性实践产生于排放物中，导致氨气中大气水平的剧烈变化。相反，在该地区北部的山区，影响大气环流的局部条件似乎比局部来源发挥着更重要的作用，当微风从该地区南部输送富含NH _3的空气团时，浓度最高。地区。