Dr Melita Keywood has made outstanding contributions to air quality, aerosol and climate science. Her research has transformed our understanding of aerosols – such as pollution from cities and bushfires – and their impacts on people, ecosystems and climate. For almost three decades, Dr Keywood has led nationally significant observing programs and contributed to the development and advancement of atmospheric observing capabilities that track changes in air pollution and the drivers of climate change. She has also built new observing technologies and research infrastructure. Her research has advanced understanding of particulate pollution in NSW and Victoria, identifying air quality policy issues and knowledge gaps. Under her leadership, long-term observations from Australia’s Kennaook/Cape Grim weather station provide some of the only Southern Hemisphere data essential for improving climate models and informing global climate and environmental assessments. She has translated scientific insights into practical outcomes, informing policies and strengthening environmental regulation and verification.