Underappreciated Emission Spikes From Power Plants During Heatwaves Observed From Space: Case Studies in India and China

The frequency, intensity, and duration of extreme heatwaves are projected to increase in the global context of climate change. However, evidence of how anthropogenic emissions respond to heatwaves and further impact air quality remains elusive. Here, we use satellite remote sensing measurements alongside chemical transport model simulations to reveal abrupt variations in primary and secondary air pollutants introduced by extreme heatwaves. We highlight evidence from China and India, where satellite sulfur dioxide (SO2) and nitrogen dioxide (NO2) columns over thermal power plants enhance consistently responding to heatwaves. We attribute such spiked emissions to soaring electricity use and demonstrate that bottom-up inventories underestimate the emissions from the power sector by 34.9% for the selected case. Elevated emissions facilitate fine particulate matter (PM2.5) and ozone (O3) formation over thermal power plants in an inhomogeneous manner, due to the combined effect of atmospheric oxidizing capacity, thermal decomposition of peroxyacetyl nitrate, planetary boundary layer rise, and air stagnation. Our results underscore the emerging challenge of pollution control attributable to the increasing climate penalty and the necessity of targeted control strategies and alternative energy sources during heatwaves. Heatwaves are associated with high ambient temperatures and adverse health outcomes, but how anthropogenic emissions of atmospheric pollutants respond to heatwaves remains less explored. Here, we provide evidence from space for the first time that sulfur dioxide (SO2) and nitrogen dioxide (NO2) over thermal power plants enhance consistently responding to heatwaves. We attribute such spiked emissions to soaring electricity use, a feedback previously overlooked by state-of-the-art emission inventories. The enhanced emissions increase levels of fine particulate matter (PM2.5) and surface ozone (O3) in an inhomogeneous manner during heatwaves due to the combined effect of chemistry and meteorology. We detect enhanced SO2 and NO2 columns over power plants during heatwaves We provide evidence of increasing electricity use and emissions in the power sector Elevated precursor emissions facilitate PM2.5 and O3 formation in an inhomogeneous manner under the combined effect of chemistry and meteorology