Assessing the Impact of Amazonian Fires on Atmospheric NO2 Using Satellite Data

In the Amazon region, the impact of fire on the region’s biogeochemical processes remains poorly understood. In this study, we examined the relationship of seasonal fire on greenhouse gas (GHG) emissions over the study region during the last two decades of the 21st century by integrating calibrated and validated satellite-derived products of estimations of burned biomass area, land cover, vegetation greenness, rainfall, carbon monoxide (CO), and nitrogen dioxide (NO2) through geospatial techniques. Results revealed a strong impact of fire activity on GHG emissions, with abrupt changes in CO and NO2 emission factors between early- and middle-dry-season fires (July–September). We found a strong positive correlation (r2 = 0.71) between NO2 and burned biomass when a small percentage of burned biomass (around ≤ 0.5%) is released during a fire. However, in the event of a large percentage of burned biomass (>0.8%), the correlation coefficient between NO2 and burned biomass was weak (r2 = 0.41). New models need to be developed that incorporate the substantial existing knowledge on the seasonal dynamics of fire-derived GHG emissions. This information should be utilized to make effective decisions about how to manage fire in the Amazon ecosystems and to drive further data collection campaigns and modelling initiatives.