To Understand Airborne Transmission of Disease, Follow the Flow

Anil Ananthaswamy (writing for Knowable, published by Annual Reviews) reports on how fluid dynamicists have spent the COVID-19 era studying the actual physics of exhalations, coughs, toilet-flush plumes, raindrops, and indoor airflow to sharpen our picture of how respiratory pathogens move through built spaces. The piece argues that the long-standing droplet-versus-aerosol dichotomy — institutionalised in WHO guidance for decades — was an artefact of bad mid-20th-century measurements, and that better fluid models are now reshaping ventilation, masking, and public-health policy.