Study Finds Flushing Toilets Release Airborne Particles
Research has revealed that flushing toilets can emit particles into the air that linger in the “breathing zone” for at least 20 seconds. Interestingly, simply closing the lid may not fully prevent these particles—potential carriers of pathogens—from escaping.
Earlier studies have identified public toilets as significant reservoirs of microbes. Researchers from Flinders University analyzed 22 studies on aerosols generated by toilets and shared their findings in the Science of the Total Environment journal.
The study indicated that microbes from the flushing water or contamination within the bowl can become airborne. They found that more forceful flushing tended to create greater amounts of aerosol particles. This encompasses bioaerosols—tiny droplets that can carry infectious agents like legionella and norovirus. However, there seems to be varied opinions on whether Covid-19 could spread through toilet aerosols.
The team noticed that increased levels of turbulence during flushing led to a higher concentration of suspended particles in the air, although the impact of bathroom ventilation and the position of the toilet lid remains uncertain.
Despite the ambiguity, lead author and PhD student Lira Adiyani still advocates for closing the lid after using the toilet. She explained, “Toilet flushing creates turbulence that can release aerosols into the surrounding air,” and highlighted that some studies have detected these aerosols at a height where adults breathe, raising concerns about possible inhalation.
Adiyani noted that a higher microbial load in toilets correlates with increased bioaerosol release, implying that toilets that use larger volumes of water for flushing generally generate more aerosols. She emphasizes that, while closing the lid may not eliminate aerosol release, it’s a reasonable precautionary step.
The study’s authors pointed out that indoor aerosol effects have been inadequately studied, which is troubling given the risks of infection they could pose. “Indoor aerosols influence air quality and human health as their small size allows them to penetrate deep into the respiratory tract when inhaled,” they remarked.
Co-author Harriet Whiley, a professor of environmental health, suggested that there’s no need for substantial worry in private homes, unless an occupant is immunocompromised. She mentioned ongoing efforts to safeguard more vulnerable populations through improved designs in facilities like hospitals.
While the immediate risks in domestic settings may seem manageable, concerns persist about “opportunistic pathogens” in water supplies, especially in recycled or rainwater. According to Whiley, while these pathogens might not impact healthy individuals significantly, they could pose serious health threats to those with weakened immune systems.
Adiyani argues for finding a way to achieve effective flushing using less water and causing less turbulence. Dr. Lotti Tajouri, an associate professor who did not participate in the research, pointed out that bathroom threats extend beyond just the toilet.
He noted his research focuses on public restrooms and the prevalence of mobile phone usage within them. “Once you enter a restroom, treat everything as contaminated,” he advises. Surfaces like the door and floor are hotspots for microbes, so people should avoid placing their belongings on them. The flushing process, particularly with the lid up, can lead to aerosol dispersal, effectively covering users in a microbial “plume.”
Even flushing with the lid down might not completely ensure safety, as previous users may have left microorganisms on various surfaces, he warned. After using the restroom, people often touch the toilet door again and then go on to interact with faucets and even their phones, spreading germs in the process.
Studies have indicated that a large percentage of individuals use their phones while in restrooms, and among younger generations, this figure is nearly universal. This habit can lead to contamination with harmful microorganisms, including salmonella and other bacteria. In summary, minimizing contact with potentially contaminated surfaces is crucial for reducing health risks.
