Several anthropogenic activities have undergone major changes following the spread of the COVID-19 pandemic, which in turn has had consequences on the environment. The effect on air pollution has been studied in detail in the literature, although some pollutants, such as ammonia (NH₃), have received comparatively less attention to date. Focusing on the case of Lombardy in Northern Italy, this study aimed to evaluate changes in NH₃ atmospheric concentration on a temporal scale (the years from 2013 to 2019 compared to 2020) and on a spatial scale (countryside, city, and mountain areas). For this purpose, ground-based (from public air quality control units scattered throughout the region) and satellite observations (from IASI sensors on board MetOp-A and MetOp-B) were collected and analyzed. For ground-based measurements, a marked spatial variability is observed between the different areas while, as regards the comparison between periods, statistically significant differences were observed only for the countryside areas (+31% in 2020 compared to previous years). The satellite data show similar patterns but do not present statistically significant differences neither between different areas, nor between the two periods. In general, there have been no reduction effects of atmospheric NH₃ as a consequence of COVID-19. This calls into question the role of the agricultural sector, which is known to be the largest responsible for NH₃ emissions. Even if the direct comparison between the two datasets shows little correlation, their contextual consideration allows making more robust considerations regarding air pollutants.

随着 COVID-19 大流行的蔓延，一些人为活动发生了重大变化，这反过来又对环境产生了影响。对空气污染的影响已在文献中进行了详细研究，尽管一些污染物，例如氨 (NH ₃ )，迄今为止受到的关注相对较少。本研究以意大利北部伦巴第大区为例，旨在评估 NH _3的变化时间尺度（2013 年至 2019 年与 2020 年相比）和空间尺度（农村、城市和山区）的大气浓度。为此，收集并分析了地面（来自分散在整个地区的公共空气质量控制单位）和卫星观测（来自 MetOp-A 和 MetOp-B 上的 IASI 传感器）。对于基于地面的测量，不同地区之间观察到明显的空间变异性，而关于时期之间的比较，仅在农村地区观察到统计上的显着差异（与往年相比，2020 年增加了 31%）。卫星数据显示出相似的模式，但在不同地区之间和两个时期之间都没有统计上的显着差异。一般来说，₃由于 COVID-19。这让人质疑农业部门的作用，众所周知，农业部门对 NH ₃排放负有最大责任。即使两个数据集之间的直接比较显示出很小的相关性，它们的上下文考虑也允许对空气污染物做出更稳健的考虑。