Effects of various physical and chemical disinfection methods on the fine particle collection efficiency of N95 respirators and surgical masks

Abstract. Current theoretical and empirical size-resolved parameterizations of the scavenging coefficient (Λ), a parameter commonly used in aerosol transport models to describe below-cloud particle scavenging by rain, have been reviewed in detail and compared with available field and laboratory measurements. Use of different formulations for raindrop-particle collection efficiency can cause uncertainties in size-resolved Λ values of one to two orders of magnitude for particles in the 0.01–3 μm diameter range. Use of different formulations of raindrop number size distribution can cause Λ values to vary by a factor of 3 to 5 for all particle sizes. The uncertainty in Λ caused by the use of different droplet terminal velocity formulations is generally small than a factor of 2. The combined uncertainty due to the use of different formulations of raindrop-particle collection efficiency, raindrop size spectrum, and raindrop terminal velocity in the current theoretical framework is not sufficient to explain the one to two order of magnitude under-prediction of Λ for the theoretical calculations relative to the majority of field measurements. These large discrepancies are likely caused by additional known physical processes (i.e, turbulent transport and mixing, cloud and aerosol microphysics) that influence field data but that are not considered in current theoretical Λ parameterizations. The predicted size-resolved particle concentrations using different theoretical Λ parameterization can differ by up to a factor of 2 for particles smaller than 0.01 μm and by a factor of >10 for particles larger than 3 μm after 2–5 mm of rain. The predicted bulk mass and number concentrations (integrated over the particle size distribution) can differ by a factor of 2 between theoretical and empirical Λ parameterizations after 2–5 mm of moderate intensity rainfall.

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Effectiveness of N95 respirators versus surgical masks in protecting health care workers from acute respiratory infection: a systematic review and meta-analysis

Canadian Medical Association Journal ◽

10.1503/cmaj.150835 ◽

2016 ◽

Vol 188 (8) ◽

pp. 567-574 ◽

Cited By ~ 118

Author(s):

Jeffrey D. Smith ◽

Colin C. MacDougall ◽

Jennie Johnstone ◽

Ray A. Copes ◽

Brian Schwartz ◽

...

Keyword(s):

Systematic Review ◽

Health Care ◽

Respiratory Infection ◽

Health Care Workers ◽

Acute Respiratory Infection ◽

Meta Analysis ◽

Care Workers ◽

Surgical Masks ◽

N95 Respirators

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Effect of Different substrate Disinfection Methods on the Production of Pleurotus ostreatus

Journal of Agricultural Studies ◽

10.5296/jas.v4i4.10051 ◽

2016 ◽

Vol 4 (4) ◽

pp. 52 ◽

Cited By ~ 2

Author(s):

Funda Atila

Keyword(s):

Rural Areas ◽

Pleurotus Ostreatus ◽

Hot Water ◽

Biological Efficiency ◽

Disinfection Methods ◽

Chemical Disinfection

AbstractThe aim of this paper is to estimate which of disinfection method is more effective in case of higher yield and fewer cost in cultivation of Pleurotus ostreatus in rural areas. For this purpose, four different treatments; scalping in hot water (60, 80 and 100°C), and chemical disinfection (1% formaldehyde) were compared with sterilization by autoclave. It has been noticed that method of disinfection affects mycelium growing duration(day), yield(g/kg), biological efficiency (BE%), avarage weight of fruitbody(g), diameter of pileus(cm), stipe lenght(cm) and width(cm). P. ostreatus took significantly much time to colonise the substrate (19.9 days) disinfected by chemical disinfection compared with others. Chemical disinfection (271.28 g/kg and 91.96%) and scalding hot water at 80oC (263.42 g/kg and 90.83%) had highest productivity in terms of yield and BE, respectively, while scalding hot water at 60oC (136.08 g/kg and 46.92%) had least productivity. The largest diameter of fruitbody was obtained by scalding in hot water at 80oC, while the longest stipes were harvested in disinfected substrate by chemicals. In conclusion, cheaper and more easily applecable scalping in hot water 80°C and chemical disinfection may be use for the disinfection of growing substrates instead of sterilization with autoclave in rural areas.Keywords: mushroom growing substrate, disinfection methods, autoclaved, scalding, chemical disinfection, Pleurotus ostreatus

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Electrohydrodynamic gas flow in a positive polarity wire-plate electrostatic precipitator and the related dust particle collection efficiency

Journal of Electrostatics ◽

10.1016/j.elstat.2005.06.006 ◽

2006 ◽

Vol 64 (3-4) ◽

pp. 259-262 ◽

Cited By ~ 57

Author(s):

Janusz Podliński ◽

Jarosław Dekowski ◽

Jerzy Mizeraczyk ◽

Drazena Brocilo ◽

Jen-Shih Chang

Keyword(s):

Dust Particle ◽

Gas Flow ◽

Electrostatic Precipitator ◽

Collection Efficiency ◽

Positive Polarity ◽

Particle Collection

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Noninvasive ventilation masks with viral filters to protect health care workers from SARS-CoV-2 / Coronavirus infections

10.21203/rs.3.rs-21269/v1 ◽

2020 ◽

Cited By ~ 2

Author(s):

Dominic Dellweg ◽

Peter Haidl ◽

Jens Kerl ◽

Dieter Koehler

Keyword(s):

Health Care ◽

Health Care Professionals ◽

Test Chamber ◽

Rubber Band ◽

Protection Measure ◽

Non Invasive ◽

Non Invasive Ventilation ◽

Care Workers ◽

Surgical Masks ◽

N95 Respirators

Abstract Background:There is a shortage of masks and respirators for the protection of health care professionals during the current SARS-CoV-2 / Coronavirus pandemic. Masks for non-invasive ventilation (NIV) in combination with viral-proof filters could serve as an alternative protection measure. We wanted to determine the aerosol filtering efficacies of such devices in comparison to conventional surgical masks, N95 and FFP3 respirators.Method:Masks and respirators were mounted on a ventilated mannequin head in a test-chamber. Absorption of radioactive particles was measured compared to a non-filtered reference port.Results: Filter efficacies were 93.3 ± 1.5 % for a ResMed AcuCare NIV-mask plus filter, 71.2 ± 0.2 % for a ResMed Mirage Quattro FX NIV-mask plus filter, 89.4 ± 0.9 % for a Loewenstein JOYCEclinc FF NIV-mask plus filter, 48.4 ± 4 % for a surgical mask with rubber band, 60.5 ± 9.1 % for a surgical mask with ribbons, 56.9 ± 7.5 % for a FFP3 respirator, 64.5 % ± 5.1 for a N95 respirator. The ResMed AcuCare and the Loewenstein JOYCEclinic FF mask were more effective than any other of the tested devices (p < 0.001 and p = 0.001 respectively)Conclusion:NIV masks with viral-proof filters effectively filter respirable particles. Two tested NIV masks were more effective than the tested FFP3 and N95 respirators.

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