From Cara Murez
HealthDay reporter
THURSDAY, April 22, 2021 (HealthDay News) – When in a public toilet, you may not want to hang around too long as there are plenty of pathogens hanging around in the air too.
Researchers from the College of Engineering and Computer Science at Florida Atlantic University performed flush tests in a public toilet with a toilet and urinal.
“After about three hours of testing with more than 100 flushes, we noticed a significant increase in the measured aerosol levels. The total number of droplets generated in each flush test was tens of thousands,” said study co-author Siddhartha Verma. He is an assistant professor of ocean and mechanical engineering at the university.
Pathogens that can cause Ebola, norovirus, and even COVID-19 can be found in stagnant water, as well as in urine, feces, and vomit. According to the research team, flushing can generate large amounts of germs in the air, depending on the flush performance, toilet design and water pressure.
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For the study, researchers placed a particle counter at different heights of the toilet and urinal to record the size and number of droplets produced by flushing. They did the same thing with a covered toilet. (Few public toilets in the U.S. have lids and urinals are uncovered.)
The droplets were detected at heights of up to 5 feet for 20 seconds or more after initiating an irrigation, the results indicated.
Investigators found fewer droplets when the lid was closed before rinsing, but the number was not much less. This indicates that aerosol droplets are escaping through small gaps between the cover and the seat.
Verma found that both the toilet and urinal produced large amounts of droplets less than 3 microns in size, which poses a significant risk of transmission if they contain infectious microorganisms.
“Because of their small size, these droplets can remain suspended for a long time,” Verma said in a university press release.
The researchers reported a 69.5% increase in measured particle quantities between 0.3 and 0.5 microns; a 209% increase for particles 0.5 to 1 micrometer in size; and a 50% increase for particles between 1 and 3 microns.
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According to Masoud Jahandar Lashaki, co-author of the study, “The significant accumulation of aerosolized droplets generated by purging over time suggests that the ventilation system was unable to effectively remove them from the enclosed space, although there was no noticeable lack of airflow in the toilet. “” Lashaki is an assistant professor of civil, environmental and geomatic engineering.
“In the long term, these aerosols could be created by updrafts generated by the ventilation system or by people moving around the toilet,” he said.
Even larger aerosols can increase the risk, the study’s authors found.
Co-author Manhar Dhanak, chairman of ocean and mechanical engineering, noted that the study suggests that “incorporating adequate ventilation into the design and operation of public spaces would help reduce the build-up of aerosols in high-altitude areas Prevent occupancy like public toilets “.
The toilet was thoroughly cleaned and closed 24 hours before the experiments were carried out, and the ventilation system was functioning normally.
The report was recently published in the journal Physics of Fluids.
Stella Batalama is the college dean of engineering and computer science. She concluded that “aerosolized droplets play a central role in the transmission of various infectious diseases including COVID-19 and this latest research by our team of scientists provides additional evidence of the risk of infection transmission in confined and poorly ventilated spaces.”
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More information
The U.S. Centers for Disease Control and Prevention has more about COVID-19.
SOURCE: Florida Atlantic University, press release, April 20, 2021
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