Questioning whether there was a short-term interaction between the 6 February 2023 earthquakes and air quality...

On 6 February 2023, Türkiye was hit by two earthquakes with 7.5 (Eq2) and 7.8 (Eq1) magnitudes. In this study, the hourly ground-level air pollutant concentrations measured in the earthquake areas were examined in detail. In addition, the remote sensing retrievals of CO, NO₂, SO₂ and CH₄ from TROPOMI instrument were also processed and investigated. The hourly mean PM_2.5 and CO increased at four stations close to the epicentre several hours prior to the earthquake. The abrupt increase in CO is likely, but PM_2.5 is probably related to the degassing activities in the faults. At the day of the earthquake, a significant TROPOMI NO₂ increase and a different spatial distribution over the region are observed. This increase coincides with the Eq2 (20 min prior) and a distinctive spatial distribution was observed on that day, indicating this signal can be associated with the earthquake or another process affected by the earthquake. On the other hand, TROPOMI CO indicated a significantly different pattern from NO₂ with lowest levels around or prior to the earthquakes, and increased levels afterwards. Limited data from TROPOMI was available for CH₄ and SO₂ due to meteorological conditions and data quality over the region to draw any conclusive findings. According to the results, it may be helpful to perform special Earth-based observations of NO₂, CO and counts of nanoparticles in the ground-based atmosphere near fault lines in seismically active belts. In addition, anomalies can also be monitored via available satellite retrievals, especially in regions with active fault lines.