Air filtration, avoidance of recirculation of air, enhanced particle filtration by suitable air filters, and air disinfection can control COVID-19 infection transmission in indoor spaces, and the use of HEPA filters, UVC light, and natural ventilation are effective methods for reducing the spread of the virus.
- Effective ventilation, avoidance of recirculation of air, enhanced particle filtration by suitable air filters and air disinfection can control COVID-19 transmission. - Opening windows can increase natural ventilation and dilute indoor air, reducing infection spread. - Indoor air purifiers with high efficiency particulate air (HEPA) filters can filter contaminated indoor air, but must be replaced regularly. - Far-UVC light is recommended for single rooms without air conditioning, while a combination of HEPA filter and UVC light can reduce bacterial and virus load significantly in air-conditioned rooms. - The supply or outdoor air should be filtered by a filter and then mixed with the recirculated air and supplied to the room through the HEPA filters. - The ASHRAE recommends HVAC systems with a minimum efficiency of Minimum Efficiency Reporting Value-13 (MERV-13) to filter even very small particles.
This is from BMC Infectious Diseases in 2021 at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8234247/.
Top five keywords: COVID-19, air filtration, indoor space, HEPA filter, infection control.
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Dear Editor,
The number of COVID-19 confirmed cases as per the WHO report is 170,747,372 and the number of deaths is 3,555,726, as on 2nd June 2021 [1]. Few countries were severely affected by the COVID-19 and the first wave predominantly affected the aged people while the second wave affected younger population significantly [2]. The elderly population and people with comorbidity, particularly diabetes is vulnerable to COVID-19. The diabetes community urgently needs to know more about COVID-19 infection control in indoor space using air filtration to avoid contracting it as the mortality figures are higher with diabetes [3]. It is reported that the vaccinees may be infected [4] and the diabetic patients are at a high risk of contracting COVID-19, if he/she visit the indoor space such as hospital where air purification is not done [5]. The severity of superspreading events such as festivals, marriage etc., depends upon the human behaviours and type of interactions [6].
It is suggested that the effective ventilation, avoidance of recirculation of air, enhanced particle filtration by suitable air filters and air disinfection can control infection transmission. The opening of windows will increase natural ventilation and dilutes the indoor air and reduces infection spread [7]. Few filters are effective in removing respiratory aerosols, however there is a misconception about air filter selection to control COVID-19 in indoor space [8]. The indoor air purifiers with high efficiency particulate air (HEPA) filter can be a used to filter the contaminated indoor air. However, this type of HEPA filters must be replaced at regular intervals [9].
If a single room without air conditioner facility is given to the patient, then the far-UVC light is recommended as it effectively controls pathogens [10], whereas rooms with air conditioning is provided for the patient, then the combination of HEPA filter and UVC light can reduce bacterial and virus load significantly [11] and this arrangement is shown in Fig. 1 . The room air can be recirculated if the HEPA filter or disinfection method is used for air filtration. The supply or outdoor air should be filtered by a filter and then it should be mixed with the recirculated air and supplied to the room through the HEPA filters [12]. The ASHRAE recommends HVAC system with minimum efficiency of Minimum Efficiency Reporting Value-13 (MERV-13) to filter even very small particles [13].
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Fig. 1
Air filtration arrangement for airconditioned room.
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Declaration of competing interest
Authors declare that, they do not have any conflict of interest.