Toilet Flushing Generates Aerosolized Pathogens, Study Finds

Researchers at Flinders University reviewed 22 prior studies of toilet-generated aerosols and published a synthesis in *Science of the Total Environment*. They reported that flushing creates turbulence that releases particles into the “breathing zone” of adults, with aerosols remaining suspended for at least 20 seconds. More turbulent, higher-volume flushes produced larger quantities of particles, and bioaerosols containing Legionella, influenza, norovirus and other microbes were detected. The study noted that the effects of bathroom ventilation and whether the lid is up or down remain unclear, but the plume can reach adult breathing height.

The Guardian

The presence of bioaerosols provides a direct exposure pathway because their small size allows deep penetration into the respiratory tract. Whiley cautioned that healthy individuals are less likely to suffer severe outcomes, but immunocompromised people could experience serious or fatal illness.

The Guardian

Lead author and PhD student Lira Adiyani advised that, based on the available evidence, closing the toilet lid after use is a prudent precaution, even though it does not fully stop aerosol escape. The research team suggested that building design and infection-control measures—particularly in hospitals and aged-care facilities—should account for aerosol generation to protect vulnerable populations.

The Guardian

• “The more microbes present in the toilet, the more bioaerosols may be released. Therefore, larger flush volumes generally produce more aerosols.” — Lira Adiyani

The Guardian

• “Indoor aerosols influence air quality and human health as their small size allows them to penetrate deep into the respiratory tract when inhaled, providing a direct exposure pathway.” — Co-author, environmental health professor Harriet Whiley

The Guardian