Impacts of Russia-Ukraine War on air pollution over the Black Sea Region due to changes in maritime transport

The Russia-Ukraine war, which began on February 24, 2022, has affected maritime transport in the Black Sea, leading to significant changes in air pollution levels in addition to other social and environmental impacts. This study examines the impact of reduced maritime activity on air pollution levels in the Black Sea by analyzing TROPOMI NO₂ and SO₂ as well as COBRA algorithm SO₂ retrievals from two years: 2019 (pre-war) and 2022 (war) along with 2019–2022 interval. To determine spatio-temporal variations, retrievals were spatially and temporally matched with EMODnet route density (RD) data. The pollution levels in the study region, over major shipping routes, and ports were examined. The results indicated that maritime traffic declined sharply around Ukrainian ports (Odessa, Kherson, and Yuzhny), while it increased in the eastern Black Sea, particularly near Russian ports (Novorossiysk and Tuapse). This shift in shipping patterns influenced NO₂ concentrations, with significant increases in the eastern regions where maritime activity intensified and decreases in the northwestern regions. In contrast, SO₂ levels showed a more complex response due to additional influences and uncertainties on SO₂ retrievals. These results highlighted the importance of satellite-based measurements in evaluating air quality impacts at offshore maritime regions with no ground-based monitoring. The study showed the complex effects of the Russia-Ukraine war on regional air pollution, demonstrating that while reduced maritime traffic led to lower pollutant concentrations in some areas, alternative shipping routes, military activities, and other factors contributed to increased pollution in others.