Agenda

Speaker: Alexis Lamothe, Institut des Géosciences de l'Environnement (IGE), Grenoble, France

Title: 300 years of NH3 inventory in Europe inferred from 15N of NH4+ in Mont-Blanc ice core with unexpected recent combustion-related emissions

Abstract:
Ammonia (NH3) abatement is a priority to limit its impact on ecosystems, biodiversity, radiative forcing, and air pollution (Gu et al., 2021). So far, the abatement policies have had limited results on the amount of NH3 emitted.
According to current European NH3 inventories, agriculture-related emissions account for 95% of NH3 sources (European Environment Agency, 2021). However, some studies are beginning to question the assumed source proportions in NH3 inventories (e.g., Chen et al., 2022).
Ice cores allow us to study past atmospheric composition. The drilling of the Col Du Dôme (Mont Blanc) in 2016 as part of the Ice Memory programme made it possible to extract 126 m of ice and thus retrace more than 300 years of European atmosphere. Here, we present a method for analysing the 15N isotopes of ammonium in ice cores (d15N(NH4+)), the deposited form of NH3, and 300 years of NH3 sources in Western Europe.
During the presentation, we will discuss the evolution of anthropogenic emissions of NH3. In particular, we show that today, only (68 ± 5) % of NH3 emissions come from agriculture, compared to 95% according to the inventories.
Our findings demonstrate the necessity to update NH3 inventories at the European scale.
In a desire to control air quality, our measurements show that public policies must now also support a reduction in NH3 emissions from vehicular, industrial, and biomass combustion.

Bio Sketch:
Third-year PhD student at the Institut des Géosciences de l'Environnement in Grenoble, he has an engineering degree in General Chemistry and a Master's degree in Chemistry from the Ecole Nationale Supérieure de Chimie de Montpellier, France. Given his background in Chemistry, he is now focusing on the reconstruction of pollution sources in Europe over the last centuries using isotope analyses of sulfur, nitrogen and oxygen in the Col Du Dôme ice core, retrieved in the context of the Ice Memory programme.