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Mechanisms by Which Ambient Humidity May Affect Viruses in Aerosols
Mechanisms by Which Ambient Humidity May Affect Viruses in Aerosols
"With prehumidification, recovery rates (± standard deviations) were much higher for nonenveloped viruses (T7 coliphage, 28% ± 19% with prehumidification versus 0.02% ± 0.01% without prehumidification; poliovirus, 29% ± 5% versus 3.2% ± 1.8%) but were unchanged for enveloped viruses (Semliki Forest virus [SFV], 32% ± 7% versus 42% ± 8%; Langat virus, 42% ± 10% versus 51% ± 12%) Benbough attributed the inactivation of nonenveloped viruses to structural rearrangement during abrupt rehydration in the impinger collection medium and suggested that slower rehydration rates, such as those experienced during the prehumidification process, were more favorable for polioviruses and coliphages" "Viruses that partition on the surface of aerosols may be subject to damage due to surface tension, shear stress, and conformational rearrangement driven by hydrophobicity." "Results showed that enveloped viruses lost infectivity dramatically (up to four orders of magnitude) due to aeration, while the nonenveloped ones did not." "Higher RH allows for larger final aerosol size and larger surface area due to less evaporation and, thus, greater potential for surface inactivation of hydrophobic lipid-containing viruses (i.e., enveloped viruses). Nonenveloped viruses are less likely to be affected." "While salts appear to be toxic to enveloped viruses, addition of salts to the medium has been shown to improve rather than reduce the viability of nonenveloped viruses... Benbough (1) suggested that salts can slow the rehydration process ... and thus reduce the chance of structural rearrangements that can be damaging in the capsid of nonenveloped viruses. Our interpretation of the enhanced viability is that salts can keep the aerosol and the virus in it from drying out completely at RHs above the ERH and thus reduce the chance of unwanted structural rearrangements during rehydration. This effect would benefit the nonenveloped viruses that need to retain their structural water; meanwhile, they are not susceptible to damage by salts, as are enveloped viruses."
·ncbi.nlm.nih.gov·
Mechanisms by Which Ambient Humidity May Affect Viruses in Aerosols
What must be done to prevent another humidifier disinfectant incident?
What must be done to prevent another humidifier disinfectant incident?
PDF | The humidifier disinfectant disaster (HDD) was not a simple poisoning accident by biocides, but a singular disaster in history created by... | Find, read and cite all the research you need on ResearchGate
·www.researchgate.net·
What must be done to prevent another humidifier disinfectant incident?
Michell Humidity Calculator
Michell Humidity Calculator
Comprehensive, user-friendly humidity calculator supporting all popular parameters including dew/frost-point, %rh, ppmV, moisture content and more.
·www.michell.com·
Michell Humidity Calculator
Methods for air cleaning and protection of building occupants from airborne pathogens
Methods for air cleaning and protection of building occupants from airborne pathogens
{Wide variety of methods}This article aims to draw the attention of the scientific community towards the elevated risks of airborne transmission of diseases and the associated risks of epidemics or pandemics. The complexity of the problem and the need for multidisciplinary research ...
·ncbi.nlm.nih.gov·
Methods for air cleaning and protection of building occupants from airborne pathogens
Summary of human responses to ventilation - PubMed
Summary of human responses to ventilation - PubMed
The review shows that ventilation has various positive impacts on health and productivity of building occupants. Ventilation reduces the prevalence of airborne infectious diseases and thus the number of sick leave days. In office environment a ventilation rate up to 20-25 L/s per person seem to decr …
·pubmed.ncbi.nlm.nih.gov·
Summary of human responses to ventilation - PubMed
The Best Humidifier of 2020 - Your Best Digs
The Best Humidifier of 2020 - Your Best Digs
{Characteristics & issues relevant to humidifier use} After 5 weeks of testing humidity and evaluating daily usability of 9 top products, we found one that stood out as the best humidifier.
·yourbestdigs.com·
The Best Humidifier of 2020 - Your Best Digs
Increasing Temperature and Relative Humidity Accelerates Inactivation of SARS-CoV-2 on Surfaces - PubMed
Increasing Temperature and Relative Humidity Accelerates Inactivation of SARS-CoV-2 on Surfaces - PubMed
Coronavirus disease 2019 (COVID-19) was first identified in China in late 2019 and is caused by newly identified severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Previous studies had reported the stability of SARS-CoV-2 in cell culture media and deposited onto surfaces under a limited s …
·pubmed.ncbi.nlm.nih.gov·
Increasing Temperature and Relative Humidity Accelerates Inactivation of SARS-CoV-2 on Surfaces - PubMed
Humidity Levels in ORs ~Anesthesia Patient Safety Foundation
Humidity Levels in ORs ~Anesthesia Patient Safety Foundation
{Organizations that regulate. Analysis of reasons for humidity guidelines} Dear Rapid Response: At our institution, we recently encountered an issue with our HVAC system that left the operating room humidity at approximately 70%. Our operating rooms were closed because...
·apsf.org·
Humidity Levels in ORs ~Anesthesia Patient Safety Foundation
Effects of personalized ventilation interventions on airborne infection risk and transmission between occupants
Effects of personalized ventilation interventions on airborne infection risk and transmission between occupants
The role of personalized ventilation (PV) in protecting against airborne disease transmission between occupants was evaluated by considering two scenarios with different PV alignments. The possibility that PV may facilitate the transport of exhaled pathogens ...
·ncbi.nlm.nih.gov·
Effects of personalized ventilation interventions on airborne infection risk and transmission between occupants
Can air purifiers protect you from the coronavirus
Can air purifiers protect you from the coronavirus
{Ways to improve home air quality.} This virus is transferred from person-to-person and can be airborne. You might think an air purifier could reduce exposure. Let’s check out
·medium.com·
Can air purifiers protect you from the coronavirus
Modeling the airborne survival of influenza virus in a residential setting: The impacts of home humidification
Modeling the airborne survival of influenza virus in a residential setting: The impacts of home humidification
********Laboratory research studies indicate that aerosolized influenza viruses survive for longer periods at low relative humidity. "indicates that increased humidification decreases survival of influenza virus on surfaces " "The median air exchange rate of the models was essentially the same, approxi- mately 0.22 air changes per hours (ACH). However, due to lower air movement between rooms, radiant heat models showed larger increases in moisture levels, and therefore larger decreases in influenza virus. In a similar way, home characteristics such as the room volume and air exchange rate should be considered"
·researchgate.net·
Modeling the airborne survival of influenza virus in a residential setting: The impacts of home humidification
Evidence Brief: Humidifier use in health care ~Public Health Ontario
Evidence Brief: Humidifier use in health care ~Public Health Ontario
"National Institutes of Health recently conducted a study to determine the risk to health of their humidifier policy.37 The policy allows patients to request bedside humidifiers, but states that humidifiers “must be filled with sterile water and that the humidifier must be discarded after three days of use.”"
·publichealthontario.ca·
Evidence Brief: Humidifier use in health care ~Public Health Ontario
Continuous measurements of air change rates in an occupied house for 1 year: The effect of temperature, wind, fans, and windows | Journal of Exposure Science & Environmental Epidemiology
Continuous measurements of air change rates in an occupied house for 1 year: The effect of temperature, wind, fans, and windows | Journal of Exposure Science & Environmental Epidemiology
***!!!!***** "Air change rates were calculated by periodically injecting a tracer gas" "Monthly average air change rates varied from 0.44 h−1 in October and November to 1.30 h−1 in July.... The mean overnight (midnight to noon) air change rate was 0.56 h−1 (0.42 SD, N=2439); mean daytime (noon to midnight) value was 0.73 h−1 (0.65 SD, N=2012). Yearly mean tracer gas decay rates were nearly identical in all rooms of the house, varying only from 0.63 to 0.68 h−1. The mean relative SD of the hourly average air change rates across all rooms (not including the attic) was 15% (SE=0.2%). The air change rate fell below 0.35 h−1 on 1087 occasions out of 4451 measurements; thus, the home fell below the recommended value (ASHRAE Standard 62) about 24% of the time." "Indoor–outdoor temperature differences had a clear effect on air change rates, with extreme temperature differences of 30°C resulting in an increase of about 0.5–0.6 air changes per hour." "experiments with keeping multiple windows open... Although higher rates of 3–4 h−1 were achieved for a brief time, the average over 12–36 h was never more than 2 h−1"
·nature.com·
Continuous measurements of air change rates in an occupied house for 1 year: The effect of temperature, wind, fans, and windows | Journal of Exposure Science & Environmental Epidemiology
Air pollutant concentrations - Wikipedia
Air pollutant concentrations - Wikipedia
"If a gaseous emission sample is analyzed and found to contain water vapor and a pollutant concentration of say 40 ppmv, then 40 ppmv should be designated as the "wet basis" pollutant concentration. "
·en.wikipedia.org·
Air pollutant concentrations - Wikipedia