The Australian New Year's wildfires in 2019/2020 sent a lot of smoke and burning products into the Southern Hemisphere's lower stratosphere. The Aura Microwave Limb Sounder tracked these plumes as they moved up. Even after the plumes dispersed, there were big changes in the stratosphere, like less HCl and more ClO and ClONO2. These changes were likely caused by chlorine reacting with smoke particles. This reaction was not as strong as in polar vortices, so it only had a small impact on ozone levels.