Through its important role in the formation of particulate matter, atmospheric ammonia affects air quality and has implications for human health and life expectancy1,2. Excess ammonia in the environment also contributes to the acidification and eutrophication of ecosystems3–5 and to climate change6. Anthropogenic emissions dominate natural ones and mostly originate from agricultural, domestic and industrial activities7. However, the total ammonia budget and the attribution of emissions to specific sources remain highly uncertain across different spatial scales7–9. Here we identify, categorize and quantify the world’s ammonia emission hotspots using a high-resolution map of atmospheric ammonia obtained from almost a decade of daily IASI satellite observations. We report 248 hotspots with diameters smaller than 50 kilometres, which we associate with either a single point source or a cluster of agricultural and industrial point sources—with the exception of one hotspot, which can be traced back to a natural source. The state-of-the-art EDGAR emission inventory10 mostly agrees with satellite-derived emission fluxes within a factor of three for larger regions. However, it does not adequately represent the majority of point sources that we identified and underestimates the emissions of two-thirds of them by at least one order of magnitude. Industrial emitters in particular are often found to be displaced or missing. Our results suggest that it is necessary to completely revisit the emission inventories of anthropogenic ammonia sources and to account for the rapid evolution of such sources over time. This will lead to better health and environmental impact assessments of atmospheric ammonia and the implementation of suitable nitrogen management strategies.Satellite observations reveal over 200 ammonia hotspots associated with agricultural and industrial point sources, which emit much larger quantities of ammonia to the atmosphere than previously thought.

中文翻译：

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工农业氨点源曝光

大气中的氨通过其在颗粒物形成中的重要作用影响空气质量，并对人类健康和预期寿命产生影响 1,2。环境中过量的氨也会导致生态系统的酸化和富营养化 3-5 以及气候变化 6。人为排放在自然排放中占主导地位，主要来自农业、家庭和工业活动 7。然而，在不同的空间尺度上，氨总收支和排放对特定来源的归因仍然高度不确定7-9。在这里，我们使用从近十年的日常 IASI 卫星观测中获得的大气氨高分辨率地图来识别、分类和量化世界上的氨排放热点。我们报告了 248 个直径小于 50 公里的热点，我们将其与单个点源或一组农业和工业点源相关联——除了一个热点，它可以追溯到一个自然源。最先进的 EDGAR 排放清单 10 大多与较大区域的卫星衍生排放通量一致，系数为 3。然而，它并不能充分代表我们确定的大多数点源，并且至少低估了其中三分之二的排放量一个数量级。尤其是工业排放源经常被发现流离失所或失踪。我们的结果表明，有必要完全重新审视人为氨源的排放清单，并考虑这些源随时间的快速演变。