Performance of mechanical filters used in general ventilation against nanoparticles

Brochot, Clothilde; Bahloul, Ali; Abdolghader, Pooya; Haghighat, Fariborz

doi:10.1088/1757-899x/609/3/032044

Cited by 6 publications

(5 citation statements)

References 6 publications

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“…First, in our former study, the measurements were taken at an aerosol diameter of 0.5 μm [10]. At that particle size, leakage through the filtration material of the respective face coverings is known to be very high [13]. e viral aerosol used in this study had a different particle size distribution (Figure 1(a)) compared to our former study.…”

Section: Discussionmentioning

confidence: 83%

High Level Bioaerosol Protection against Infective Aerosols: How Medical Face Masks Compare against Respirators

Sterr

Dick

Schellenberger

et al. 2022

Canadian Journal of Infectious Diseases and Medical Microbiolog

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Face masks and respirators are commonly used to prevent the transmission of infectious diseases that spread by respiratory droplets and aerosols. However, there is still uncertainty about the protective effect of the different types of masks against virus containing aerosols. To determine the as-worn bioaerosol protection efficacy of different face coverings and estimate the possible protective function against airborne diseases, we challenged different respirators and medical masks on a standardized dummy head with a bioaerosol containing MS2 bacteriophages as virus surrogates. In our experiments, FFP2 respirators showed the highest filtration efficacy 94 ± 4 (SD) % followed by medical masks 93 ± 3 (SD) % and KN95 respirators 90 ± 7 (SD) %. Nevertheless, we found no statistically significant difference between respirators and medical masks in terms of provided protection against infective aerosols. Our findings indicate that both respirators and medical masks provide a high as-worn bioaerosol protection efficacy against virus containing aerosols, and therefore, a very high protection against airborne diseases. Considering the higher comfort, better availability, and lower price of medical masks in contrast to respirators, it is recommendable to use medical face masks especially in low risk situations and in general public.

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Section: Discussionmentioning

confidence: 83%

High Level Bioaerosol Protection against Infective Aerosols: How Medical Face Masks Compare against Respirators

Sterr

Dick

Schellenberger

et al. 2022

Canadian Journal of Infectious Diseases and Medical Microbiolog

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“…Brochot et al 38 explored the most penetrating particle size of different commercial filters and found that the 150–500 nm range provides a better estimation of the MPPS in size range of 20–500 nm. Hanley et al 24 found that a minimum filtration efficiency often occurred in the 0.1–0.5 μm diameter size range.…”

Section: Resultsmentioning

confidence: 99%

“…theoretical efficiency predicts the most penetrating particle size occurs around 0.3 μm, it is reported that smaller particles may show the lowest removal efficiency at a higher velocity. 37 Brochot et al 38 explored the most penetrating particle size of different commercial filters and found that the 150-500 nm range provides a better estimation of the MPPS in size range of 20-500 nm.…”

Section: Particle Size Removal Efficiencies Of Filtersmentioning

confidence: 99%

Filter evaluation and selection for heating, ventilation, and air conditioning systems during and beyond the COVID ‐19 pandemic

Chen

Olfert

et al. 2022

Indoor Air

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Particle size removal efficiencies for 0.1-1.0 μm (PSE 0.1−1.0 ) and 0.3-1.0 μm (PSE 0.3−1.0 ) diameter of Minimum Efficiency Reporting Value (MERV) filters, an electrostatic enhanced air filter (EEAF), and their two-stage filtration systems were evaluated. Considering the most penetrating particle size was 0.1-0.4 μm particulate matter (PM), the PSE 0.1−1.0 as an evaluation parameter deserves more attention during the COVID-19 pandemic, compared to the PSE 0.3−1.0 . The MERV 13 filters were recommended for a single-stage filtration system because of their superior quality factor (QF) compared to MERV 6, MERV 8, MERV 11 filters, and the EEAF. Combined MERV 8 + MERV 11 filters have the highest QF compared to MERV 6 + MERV 11 filters and EEAF + MERV 11 filters; regarding 50% of PSE 0.1−1.0 as the filtration requirements of two-stage filtration systems, the MERV 8 + MERV 11 filtration system can achieve this value at 1.0 m/s air velocity, while PSE 0.1−1.0 values were lower than 50% at 1.5 m/s and 2.0 m/s. EEAF obtained a better PSE 0.3−1.0 in the full-recirculated test rig than in the single-pass mode owing to active ionization effects when EEAF was charged by alternating current.

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“… 21 , 22 In addition, 0.3 µm allows for a worst-case evaluation of filtration approaches as this is the most penetrating particle size for N95 respiratory masks and corresponds to MERV (Minimum Efficiency Reporting Value) criteria for HVAC (Heating, Ventilation, and Air Conditioning) filter media which can vary within a range of 150 to 500 nm depending on particles’ shape, charge, or relative humidity. 23 …”

Section: Methodsmentioning

confidence: 99%

Fate of Exhaled Droplets From Breathing and Coughing in Supermarket Checkouts and Passenger Cars

Nishandar

Princevac

et al. 2023

Environ�Health�Insights

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The global pandemic of COVID-19 has highlighted the importance of understanding the role that exhaled droplets play in virus transmission in community settings. Computational Fluid Dynamics (CFD) enables systematic examination of roles the exhaled droplets play in the spread of SARS-CoV-2 in indoor environments. This analysis uses published exhaled droplet size distributions combined with terminal aerosol droplet size based on measured peak concentrations for SARS-CoV-2 RNA in aerosols to simulate exhaled droplet dispersion, evaporation, and deposition in a supermarket checkout area and rideshare car where close proximity with other individuals is common. Using air inlet velocity of 2 m/s in the passenger car and ASHRAE recommendations for ventilation and comfort in the supermarket, simulations demonstrate that exhaled droplets <20 μm that contain the majority of viral RNA evaporated leaving residual droplet nuclei that remain aerosolized in the air. Subsequently ~ 70% of these droplet nuclei deposited in the supermarket and the car with the reminder vented from the space. The maximum surface deposition of droplet nuclei/m2 for speaking and coughing were 2 and 819, 18 and 1387 for supermarket and car respectively. Approximately 15% of the total exhaled droplets (aerodynamic diameters 20-700 µm) were deposited on surfaces in close proximity to the individual. Due to the non-linear distribution of viral RNA across droplet sizes, however, these larger exhaled droplets that deposit on surfaces have low viral content. Maximum surface deposition of viral RNA was 70 and 1.7 × 103 virions/m2 for speaking and 2.3 × 104 and 9.3 × 104 virions/m2 for coughing in the supermarket and car respectively while the initial airborne concentration of viral RNA was 7 × 106 copies per ml. Integrating the droplet size distributions with viral load distributions, this study helps explain the apparent importance of inhalation exposures compared to surface contact observed in the pandemic.

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Performance of mechanical filters used in general ventilation against nanoparticles

Cited by 6 publications

References 6 publications

High Level Bioaerosol Protection against Infective Aerosols: How Medical Face Masks Compare against Respirators

High Level Bioaerosol Protection against Infective Aerosols: How Medical Face Masks Compare against Respirators

Filter evaluation and selection for heating, ventilation, and air conditioning systems during and beyond the COVID ‐19 pandemic

Fate of Exhaled Droplets From Breathing and Coughing in Supermarket Checkouts and Passenger Cars

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