COVID-19 Virus Found in the Air and on Surfaces of Hospital Rooms
Key takeaway.
SARS-CoV-2 was detected in the air, on bathroom fixtures used by patients, and on air exhaust vents of hospital rooms housing COVID-19 patients. The study did not sample floor drains, but its findings of positive air samples and contaminated exhaust vents point to the movement of virus-laden aerosols through a room's air pathways.
The study.
Published in Nature Communications, one of the highest-impact scientific journals, this study provided early and significant evidence that SARS-CoV-2 could be detected both in the air and on surfaces within hospital rooms of COVID-19 patients. The research team at Singapore's National Centre for Infectious Diseases sampled air and high-touch surfaces in isolation rooms during the early months of the pandemic.
They found viral RNA on a wide range of surfaces, including bed rails, light switches, toilet seats and flush buttons, sink basins, and the room floor. Toilet and bathroom surfaces tested positive for SARS-CoV-2 RNA, consistent with documented fecal shedding of the virus. Air samples were also positive in some rooms, particularly those housing patients during the first week of illness when viral shedding is highest. The study did not sample or report on floor drains.
Notably, viral RNA was detected on air exhaust vents in the patient rooms, suggesting that virus-laden aerosols can travel beyond the immediate patient vicinity through a room's air-handling pathways. Environmental sampling was performed before the daily cleaning cycle, so the study did not assess whether contamination persisted after cleaning.
Key findings.
- Virus found throughout patient rooms SARS-CoV-2 was detected on bed rails, light switches, toilet seats and flush buttons, sink basins, and the room floor, confirming that infected patients shed the virus extensively onto their surrounding environment.
- Toilet and bathroom surfaces tested positive Toilet seats, flush buttons, and sink surfaces tested positive for SARS-CoV-2 RNA. This is consistent with documented gastrointestinal shedding of the virus, which reaches the drainage system through the toilet.
- Virus detected in air samples SARS-CoV-2 RNA was found in air samples, particularly in rooms with patients during the first week of illness when viral shedding is highest, supporting the aerosol transmission pathway.
- Air exhaust vents contaminated Viral RNA was recovered from the air exhaust vents in patient rooms, showing that virus-laden aerosols can reach a room's air-handling openings rather than staying at the patient's bedside.
- Aerosol spread beyond the bedside The combination of positive air samples and contaminated air exhaust vents indicates that airborne particles carrying the virus travel beyond the immediate patient vicinity, a concern for how air moves through a building's spaces.
What this means for your facility.
This study connects the COVID-19 pandemic directly to the building infrastructure vulnerability that Green Drain is engineered to address. The 2003 SARS outbreak at Amoy Gardens in Hong Kong demonstrated that dried P-traps in a residential building's drainage system allowed viral aerosols to travel between apartments, infecting over 300 residents and killing 42. Chia and colleagues' finding of SARS-CoV-2 in patient-room air and on bathroom surfaces, together with documented gastrointestinal shedding that reaches the drainage system, points to the same category of air-pathway vulnerability. Green Drain's silicone one-way valve restricts the upward air-and-aerosol pathway: it allows water and waste to flow down while restricting the backflow of air, gas, and aerosol from the drainage system below.
Green Drain's role is limited to the air-and-aerosol pathway between the drainage system and the room. In an independent SGS bench test (Report QDF25-0049810-01), the GD3 model physically retained over 99.9% of an aerosolized MS2 bacteriophage, a non-enveloped RNA virus used as a conservative surrogate, in a controlled test setup. This is a measurement of physical retention of a surrogate under bench conditions, not a measurement against any real pathogen, infection, or dispersal risk; surrogate retention is not pathogen retention. No study, including this one, has tested a trap-seal barrier against a viral or infection endpoint. No other waterless trap seal product on the market has published comparable aerosol-retention data.
Surface cleaning acts only on the surfaces it reaches and only for as long as staff keep up with it. Green Drain works on a different problem entirely: it is a continuous, passive engineering control on the drain opening that restricts the upward movement of air and aerosols around the clock, without staff intervention, without chemical inputs, and without the risk of human error. It does not remediate or remove an existing biofilm, and it complements rather than replaces cleaning and infection-prevention protocols. Once installed as a drop-in with no tools required, it simply works. The ASSE 1072-2020 life cycle test confirmed the GD4 performs identically after 2,500 open-close cycles.
This study is not just a historical document about COVID-19. It represents a category of risk that will recur with future respiratory and enteric pathogens. Green Drain's value does not depend on any single pathogen. It restricts the upward movement of air and aerosols from the plumbing system into occupied spaces. For healthcare facilities, food processing plants, hotels with seasonal occupancy, schools with summer breaks that leave traps dry for months, and any building with infrequently used drains, this is infrastructure-level preparedness at roughly $40 per drain point.
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Green Drain's waterless trap seal is a supportive engineering control that restricts the upward movement of air and aerosols, backed by independent bench testing. See how it works for your industry.