Spaceborne NO₂ observations are sensitive to coal mining and processing in the largest coal basin of Russia

Coal use exacerbates several major environmental problems including build-up of greenhouse gases and air quality deterioration. Although Kuzbass (Siberia) is one of the largest exploited coal basins worldwide, the role of regional coal mining and processing in atmospheric pollution is unknown. We outlined the Kuzbass coal basin by spaceborne night-lights and revealed a regional, long-term tropospheric NO₂ anomaly (2005-2018) by spaceborne NO₂ column observations (hereafter ‒ NO₂). The spatial agreement between NO₂ and night-lights indicates that the anomaly is attributable to an agglomeration of coal quarries and the cities in Kuzbass, that are heavily reliant on coal. A positive relationship between NO₂ and interannual coal production suggested that the anomaly was related to coal in Kuzbass; ~ 1.0% of annual coal production increase induced ~ 0.5-0.6% of NO₂ enhancement. As coal production accelerated since 2010, NO₂ exhibited strikingly similar annual increases over Kuzbass in 2010-2014 (7%) and 2015-2019 (15%), compared to 2005-2009. Conversely, Siberian cities lacking a coal industry followed the global trend of reducing NO₂ for the same periods (-5% and -14%, respectively), driven by fuel combustion improvements. Overall, we demonstrated that coal mining, processing and utilization can induce distinct tropospheric NO₂ anomalies, detectable from space.