Abstract:Engineering controls play an important role in reducing the spread of SARS-CoV-2 (1). Established technologies such as air filtration and novel approaches such as UV-C light or plasma air ionization carry the potential to support the fight against the pandemic (2). We tested the efficacy of an air purification system (APS) combining UV-C light and High Efficiency Particulate Air (HEPA) filtration in a controlled environment using SARS-CoV-2 as test organism. The APS successfully removed the virus from the air … Show more
“…As such, vulnerable patients who are at some distance (>2 m) from an infector can become exposed [26]. Realisation of this issue has led to growing interest in non-pharmaceutical interventions such as supplementary room air filtration [27] and air disinfection [28, 29], and also utilising carbon dioxide (CO 2 ) monitoring [30, 31] to optimise ventilation [32]. These aim to mitigate the transmission of SARS-CoV-2 in clinical settings, and it is within this context that we report our findings.…”
Background
During the COVID-19 pandemic, aerosol spread of SARS-CoV-2 has been a major problem in healthcare facilities, resulting in increased use of supplementary HEPA filtration to mitigate transmission. We report here a natural experiment that occurred when an air filtration unit (AFU) on an inpatient ward for older people was accidentally switched off.
Aim
To assess aerosol transport within the ward and determine whether the AFU reduced particulate matter (PM) levels in the air.
Methods
Time-series PM, CO2, temperature and humidity data (at 1 minute intervals) was collected from multiple sensors around the ward over two days in August 2021. During this period, the AFU was accidentally switched off for approximately 7 hours, allowing the impact of the intervention on particulates (PM1-PM10) to be assessed using a Mann-Whitney test. Pearson correlation analysis of the PM and CO2 signals was also undertaken to evaluate the movement of airborne particulates around the ward.
Findings
The AFU greatly reduced PM counts of all sizes throughout the ward space (p<0.001 for all sensors), with PM signals positively correlated with indoor CO2 levels (r = 0.343-0.817; all p<0.001). Aerosol particle counts tended to rise and fall simultaneously throughout the ward space when the AFU was off, with PM signals from multiple locations highly correlated (e.g. r = 0.343-0.868 (all p<0.001) for PM1).
Conclusion
Aerosols freely migrated between the various sub-compartments of the ward, suggesting that social distancing measures alone cannot prevent nosocomial transmission of SARS-CoV-2. The AFU greatly reduced PM levels throughout the ward space.
“…As such, vulnerable patients who are at some distance (>2 m) from an infector can become exposed [26]. Realisation of this issue has led to growing interest in non-pharmaceutical interventions such as supplementary room air filtration [27] and air disinfection [28, 29], and also utilising carbon dioxide (CO 2 ) monitoring [30, 31] to optimise ventilation [32]. These aim to mitigate the transmission of SARS-CoV-2 in clinical settings, and it is within this context that we report our findings.…”
Background
During the COVID-19 pandemic, aerosol spread of SARS-CoV-2 has been a major problem in healthcare facilities, resulting in increased use of supplementary HEPA filtration to mitigate transmission. We report here a natural experiment that occurred when an air filtration unit (AFU) on an inpatient ward for older people was accidentally switched off.
Aim
To assess aerosol transport within the ward and determine whether the AFU reduced particulate matter (PM) levels in the air.
Methods
Time-series PM, CO2, temperature and humidity data (at 1 minute intervals) was collected from multiple sensors around the ward over two days in August 2021. During this period, the AFU was accidentally switched off for approximately 7 hours, allowing the impact of the intervention on particulates (PM1-PM10) to be assessed using a Mann-Whitney test. Pearson correlation analysis of the PM and CO2 signals was also undertaken to evaluate the movement of airborne particulates around the ward.
Findings
The AFU greatly reduced PM counts of all sizes throughout the ward space (p<0.001 for all sensors), with PM signals positively correlated with indoor CO2 levels (r = 0.343-0.817; all p<0.001). Aerosol particle counts tended to rise and fall simultaneously throughout the ward space when the AFU was off, with PM signals from multiple locations highly correlated (e.g. r = 0.343-0.868 (all p<0.001) for PM1).
Conclusion
Aerosols freely migrated between the various sub-compartments of the ward, suggesting that social distancing measures alone cannot prevent nosocomial transmission of SARS-CoV-2. The AFU greatly reduced PM levels throughout the ward space.
“…Eighteen records were assessed for eligibility and 13 were included in this review ( 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ). Five studies were excluded because they did not meet our inclusion criteria, i.e., two studies did not provide enough information about the UVC system ( 23 , 24 ), one did not present quantitative data for SARS-CoV-2 inactivation ( 25 ), one reported data using SARS-CoV-2 surrogates ( 26 ) and one used UVA-based technology ( 27 ) ( Figure 2 ). Figure 2 PRISMA flowchart for studies included in this review.…”
A significant amount of epidemiological evidence has underlined that human-to-human transmission due to close contacts is considered the main pathway of transmission, however since the SARS-CoV-2 can also survive in aerosols, water, and surfaces, the development and implementation of effective decontamination strategies are urgently required. In this regard, ultraviolet germicidal irradiation (UVGI) using ultraviolet C (UVC) has been proposed to disinfect different environments and surfaces contaminated by SARS-CoV-2. Herein, we performed a systematic scoping review strictly focused on peer-reviewed studies published in English that reported experimental results of UVC-based technologies against the SARS-CoV-2 virus. Studies were retrieved from PubMed and the Web of Science database. After our criterious screening, we identified 13 eligible articles that used UVC-based systems to inactivate SARS-CoV-2. We noticed the use of different UVC wavelengths, technologies, and light doses. The initial viral titer was also heterogeneous among studies. Most studies reported virus inactivation in well plates, even though virus persistence on N95 respirators and different surfaces were also evaluated. SARS-CoV-2 inactivation reached from 90% to 100% depending on experimental conditions. We concluded that there is sufficient evidence to support the use of UVC-based technologies against SARS-CoV-2. However, appropriate implementation is required to guarantee the efficacy and safety of UVC strategies to control the COVID-19 pandemic.
“…The unit has an internal HEPA filter and ultraviolet lamps for decontamination of the airstream, and a centrifugal fan that generates approximately −2.5 Pa of negative pressure. When challenged by SARS-CoV-2 bioaerosols, this air disinfection technology has been shown to effectively eliminate the virus 5…”
IntroductionSpontaneously breathing patients undergoing procedures under regional anesthesia can expose operating room personnel to infectious agents. The use of localized negative pressure within proximity of a patient’s airway is expected to reduce the amount of bioaerosols dispersed particularly for anesthesia staff who are frequently near the patient’s airway.MethodsIn the experiment, aerosols were produced using a polydisperse aerosol generator with nebulized saline. A portable negative pressure unit was set up at set distances of 10 cm and 30 cm with the aim of reducing aerosol particle counts detected by a laser-based particle counter.ResultsWithout the portable negative pressure unit, the median concentration of 0.5 µm aerosols detected was 3128 (1533, 22832) particles/ft3/min. With the portable negative pressure unit 10 cm and 30 cm from the site of aerosol emittance, the median concentration compared with background concentration was −0.5 (−8, 8) particles/ft3/min and 398 (89, 1749) particles/ft3/min, respectively.ConclusionsFor particle concentrations of 0.5 µm, 0.7 µm, and 1.0 µm a significant amount of aerosol reduction was observed (p<0.001). Further experiments are warranted to assess the safety of staff when encountering a potentially infectious patient in the operating room.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
