Temporal variability of NH3 in European hot spots based on satellite and in-situ observations

Ammonia (NH₃) is primarily emitted from agricultural sources, including livestock farming and fertilizer application. Animal farms are significant contributors to ammonia emissions, particularly under low rainfall, as rainfall typically leads to nitrogen leaching and ammonia removal from the soil. In addition to agricultural activities, combustion-related NH₃ emissions, primarily from fossil fuel burning and biomass combustion, also contribute to atmospheric ammonia; however, these sources remain poorly understood. Ammonia emissions mainly arise from the volatilization of NH₃ from NH₄⁺-containing substrates, such as fertilized soils, animal waste, and nitrogen-polluted water, as well as from combustion-related processes, including coal combustion, vehicle exhaust, and biomass burning.

Ammonia significantly impacts air quality as a precursor to fine particulate matter (PM2.5), which has considerable health implications. A study by Vieno et al. (2016) (https://acp.copernicus.org/articles/23/15253/2023/)  demonstrated that reducing NH₃ emissions in the United Kingdom could lower PM2.5 levels. Despite this recognized impact, NH₃ monitoring networks are inconsistently implemented across Europe, with only a few countries, such as the Netherlands, the UK, and Belgium, maintaining dedicated NH₃ monitoring systems. Projections indicate that NH₃ emissions are likely to increase due to rising global temperatures and the growing demand for animal products, emphasizing the need for accurate, traceable, and routine NH₃ monitoring to better understand the complexities of ammonia in the atmosphere.

This study aims to identify NH₃ hot-spot regions in Europe based on satellite data from METOP IASI for 2019 to 2022 and compare these findings while accounting for surface variability and reported emission sources. Furthermore, we explore NH₃ CAMS profile analysis and NH₃ observations from the EBAS database of atmospheric measurements.