Air quality monitoring in Ukraine during 2022 military conflict using Sentinel-5P imagery

Air quality assessment is an important task, due to the adverse effects of air pollution on human health. This importance is more highlighted when it comes to exceptional events such as war. Early 2022 witnessed the start of a military conflict between Ukraine and Russia. As with any similar event, this war influences the environment in different aspects. The objective of this study is air quality monitoring in Ukraine using Sentinel-5P imagery and Google Earth Engine. To this end, the monthly concentration of four gaseous pollutants including ozone (O₃), nitrogen dioxide (NO₂), formaldehyde (HCHO), and carbon monoxide (CO) in 2022 is compared to 2019 and 2021 as business-as-usual (BAU) periods. Further statistical focus of this evaluation is on five major cities, namely Kiev, Kharkiv, Donetsk, Kherson, and Lviv. According to the results, the general trend of the O₃ concentration is found to be increasing, whereas NO₂, HCHO, and CO follow mostly a decreasing trend. However, the records of Lviv in terms of NO₂ and HCHO indicate significant discrepancies with other cities that are deemed warfronts. Moreover, based on the applied t-test, the differences between the 2022 concentrations and BAU years in most cases are statistically significant. In summary, this study revealed evident effects of the ongoing war on the anthropogenic activities in Ukraine and, consequently, changes in air pollution.