English: During the last ten days of June 2020, the Sakha Republic (Russia) experienced a heatwave during which many areas within the Arctic Circle registered temperatures above 35°C for several days in a row. One of the consequences of these extreme temperatures was the triggering of multiple wildfires that devastated extended areas of forest and tundra, while releasing large amounts of Carbon Monoxide (CO) into the atmosphere. This image shows the average value of CO for the period June 21 - June 30, obtained from the data retrieved by the Copernicus Sentinel-5P satellite, for the Sakha Republic: in the Srednekolymsky district, where some fires have burned an area of over 100,000 ha, atmospheric CO for the period reached 0.06 mol/m2 (an increase of 120% compared to the same period of 2019). Carbon monoxide (CO) is an important atmospheric constituent affecting air quality: detailed and continuous observations of CO are necessary to better assess its impact on climate and atmospheric pollution. The TROPOspheric Monitoring Instrument (TROPOMI) onboard the Copernicus Sentinel-5P satellite allows the measurement of CO levels with an unprecedented level of detail on a global scale, with a revisit time of one day.