Toilet Flushing Releases Bioaerosols; Closing the Lid Reduces but Doesn’t Eliminate Risk

A review of 22 studies finds toilet flushing can eject microbes as aerosols into the air for at least 20 seconds, and closing the lid does not fully prevent exposure, though it may reduce it. Turbulent flushes generate more particles, and higher microbial loads increase bioaerosol release, with potential pathogens including Legionella, influenza and norovirus. Ventilation effects remain unclear, but the findings underscore implications for building design and infection control—especially in hospitals and care settings—advocating lower-volume flushes and lid use as precautionary measures rather than guarantees of safety.