Researchers from Flinders University have discovered that flushing toilets can release tiny particles, known as aerosols, and particles containing microorganisms, called bioaerosols, into the air. These particles can reach the height of a person's breathing zone, potentially allowing them to be inhaled. The findings, published in the journal Science of the Total Environment, come from a comprehensive review of 22 studies that examined how aerosols are generated and dispersed during toilet flushing. Lead author Lira Adiyani, a Ph.D. student at Flinders University, explains that the turbulence created by flushing can lift these particles into the air. Some studies have found these aerosols at the level where adults breathe, suggesting a possible route for exposure to disease-causing microbes. The study found that the amount of microbes in toilet water significantly affects the number of bioaerosols released. More microbes in the toilet bowl or in the water used for flushing can lead to higher concentrations of bioaerosols in the air. The research also looked at both controlled experiments, where microorganisms were intentionally added to the water, and real-world conditions where no microbes were introduced. The results showed that aerosol levels varied depending on factors like the type of toilet, how it was used, and the methods used to measure the particles. Aerosol concentrations were typically highest near the toilet, especially around the height of the toilet seat. This suggests that maintaining good toilet hygiene—such as regularly cleaning the toilet and surrounding areas, and washing hands after use—may help reduce the risk of microbial exposure. The volume of water used during flushing was also found to influence aerosol production, with larger flush volumes generating more aerosols. The study suggests that using toilets with lower flush volumes or selecting the lower-volume option on dual-flush toilets could help reduce aerosol generation. Aerosols were observed to remain in the air for at least 20 seconds after flushing. While the review found no strong link between ventilation or lid position and aerosol concentration, it noted that proper ventilation could help disperse airborne particles. Closing the toilet lid before flushing might also change how aerosols spread, with some studies suggesting that closed lids can prevent aerosols from rising directly upward. While closing the lid doesn't completely stop aerosols from escaping, it may help reduce inhalation risk. Researchers emphasize that more studies are needed to improve toilet design and ventilation strategies, especially in high-risk environments like hospitals, to further minimize the spread of airborne microbes.