Atmospheric deposition of nitrogen and sulphur in the Dniester catchment: the impact of war at a glance

Burning of fossil fuels, application of fertilisers, and livestock farming have greatly increased emissions of reactive nitrogen (N). The consequent increase in atmospheric deposition of N compounds has compromised air, soil and water quality, ecosystems, and human health and wellbeing. Sulphate aerosols also affect climate dynamics by scattering solar radiation, leading to surface cooling and, indirectly, cloud formation and precipitation. During 2021 (the pre-war year), the rates of total N deposition over the lower, middle and upper parts of the Dniester catchment were 21.8 ± 1.7, 17.0 and 19.0 ± 3.1 kgN/ha, respectively. The war in Ukraine brought a 35% decrease in annual total N deposition within the Lower Dniester region as a consequence of economic disruption and population displacement. In contrast, the influx of refugees and business relocation to the middle and upper parts of the basin counteracted the impacts of war, resulting in a slight increase (ca. 4%) or no change in cumulative total N deposition during 2022 compared to the pre-war year. The pre-war rates of sulphate deposition were 2.8 ± 0.1, 2.8 and 3.2 ± 0.1 kgS/ha for the lower, middle and upper basin: these were reduced 11–15%. These findings emphasise that local and regional factors interact. Peace is a prerequisite for reducing N emissions and safeguarding the environment.