High-efficiency particulate air (HEPA) filter is widely use in medical and industrial clean rooms to filter air particulate and capture air-borne pathogens. In regarding to question, whether Air Purifier with HEPA filter is efficiently capture the virus that caused the COVID-19 virus, the answer is obviously – Yes.
Evidences have showed that Covid 19 is spread through airborne transmission, via small droplets, aerosol and particles that can linger in the air for minutes to hours.
For more information, you may check out this publication “How the coronavirus is spread through the air” (1)
How is HEPA filter efficient and effective ?
The virus that causes COVID-19 is approximately 0.125 micron (125 nanometers) (3) in diameter. It falls squarely within the particle-size range that HEPA filters capture with extraordinary efficiency: 0.01 micron (10 nanometers) and above. NASA publication (3) about HEPA filtration explained why HEPA filter is actually the most efficient filter—almost 100% at 0.01 micron—at capturing ultra-fine particles below the 0.3-micron HEPA test standard.
Please see the figures below :
i. Efficiency of HEPA filter ranging from 0.01 micron to 10 micron, The filter test is done at 0.3 micron, with 99.995% efficiency. At 0.125 micron, the efficiency is much higher than 99.995%.
ii. The 3 mechanism of how HEPA filter capture and filter virus, bacteria and air particulate : a. Diffusion, b. Interception and c. Inertial Impaction (different mechanism according to sizes from 0.01 – 10 micron)
iii. The structure of HEPA Media showed in SEM (Microscope)
This means HEPA purifiers would efficiently capture viruses (and any aerosolised droplets of saliva and mucus). CDC recognised that : “When used properly, air purifiers can help reduce airborne contaminants, including viruses, in a home or confined space. And in its guidance for health-care personnel, the CDC states that air from rooms where COVID-19 patients are being isolated “should be exhausted directly to the outside or be filtered through a high-efficiency particulate air (HEPA) filter directly before recirculation” . Inline with CDC, ASHRAE (The American Society of Heating, Refrigerating and Air-Conditioning Engineers) Epidemic Task Force (4) also recommending filtration (including HEPA filter) and uv light as the recommended mitigation strategy to improve the indoor air quality to prevent spreading of diseases.
What is the best practices for air purifier with HEPA filter ?
According to a study by the Goethe University in Frankfurt (5), mobile air purifiers with HEPA air filters can help to reduce the virus concentration by 90% within half an hour. On another independent study by Aerosol Research & Engineering Laboratories (6), using Erlab’s HALO P Ceiling Mounted Air Purifier with HEPA filter, also show that a reduction of 99.99% of viruses at 90 min and 90% in just 15 min.
If there is a super‐spreader in the room, air purifier with HEPA filter reduces the risk of infection. To this end, the following requirements must be met by room air filtration systems:
- A room air filtration unit should be able to filter 3-5 times the room volume, we also call this 3-5 times air change per hour. For a room with approx. 20 m² and a wall height of 3 m, therefore, approx. 300 cubic metres of air per hour must be filtered in order to reach 5 times air change per hour.
- The filtration unit should include pre filter (removal of course dust) and HEPA air filter with class H13 or H14 to achieve a separation efficiency of ≥99.95% or ≥99.995% for the relevant particle spectrum with a diameter of 0.01-0.3 µm.
- The filtration unit should be placed in the middle of the room, and preferably mounted on the ceiling to create the best air circulation and exchange in the room. The air inlet and outlet should not be blocked by object, wall or interfering the room air conditions system
- The filtration unit should be able to operate as quietly as possible. Here, the air filters influence the noise pollution through their design and the pressure difference generated.
- The filtration unit should also have low energy consumption and durable to filter long period of time.
A Ceiling Mounted Laboratory-grade Air Purification System with H14 HEPA filter – HALO P
Halo P Smart air purifier capture viruses, bacteria, allergens and all dust and particulate matter at the source and trap them permanently in a high-efficiency H14 HEPA filter with multiple layers of bonded glass microfibers. Originally developed to capture pathogens (viruses, bacteria, etc.) from the air during handling in biology laboratories, Halo P Smart air purifiers are recommended for any enclosed or poorly ventilated space where people gather. In response to the COVID-19 pandemic, they are particularly suitable for spaces which make wearing a mask impossible (restaurants, long-term care facilities, clinic, banks, lobby and school dining halls, etc.) or difficult (gyms), as well as in places where social distancing is difficult (enclosed offices, elevators, & etc.).
HALO P Smart Air Purifier with HEPA Filter is tested by third party in vitro study to characterise the efficacy of it filtration.(6) Halo P Smart Air Purifier is proven to be able to remove aerosolised viruses effectively in a very short time. The study showed a steady net log reduction in a relatively short amount of time with average log reduction values ranging from 0.82 average net Log in 15 minutes to 4.13 average net log reduction in 90 minutes. (90% reduction with 15 min, 99.99% at 90 min filtration time using HALO P Smart Air Purifier. These filters are designed for the most complex sanitary situations. They efficiently and significantly reduce the propagation of all airborne viral and bacterial pollutants. These types of filters are found in clean-rooms and in all laboratory grade microbiological safety cabinets for the safe handling of pathogenic microorganisms. If fulfil all the criteria listed above, and it also able to remotely control using a smart phone.
Find out more about HALO P filtration unit at this link : https://tms-lab.com/product/halo-p-smart-air-purifier/
Do contact us for more information and find out our latest offer.
Reference :
(1) https://english.elpais.com/society/2020-10-28/a-room-a-bar-and-a-class-how-the-coronavirus-is-spread-through-the-air.html
(2) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4369385/
(3) https://ntrs.nasa.gov/api/citations/20170005166/downloads/20170005166.pdf
(4) https://www.ashrae.org/file%20library/technical%20resources/covid-19/ashrae-covid19-infographic-.pdf
(5) Curtius, J. et al (2020): Testing mobile air purifiers in a school classroom: Reducing the airborne transmission risk for SARS-CoV-2.
(6) Sean McLeod a, Jeffery Trolinger (2020) Efficacy of the Erlab Halo P Device against Aerosolised MS2 Virus
