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Full-Text Articles in Public Health
Influenza Virus Infectivity Is Retained In Aerosols And Droplets Independent Of Relative Humidity, Karen A. Kormuth, Kaisen Lin, Aaron J. Prussin, Eric P. Vejerano, Andrea J. Tiwari, Steve S. Cox, Micheal M. Myerburg, Seema S. Lakdawala, Linsey C. Marr
Influenza Virus Infectivity Is Retained In Aerosols And Droplets Independent Of Relative Humidity, Karen A. Kormuth, Kaisen Lin, Aaron J. Prussin, Eric P. Vejerano, Andrea J. Tiwari, Steve S. Cox, Micheal M. Myerburg, Seema S. Lakdawala, Linsey C. Marr
Faculty Publications
Pandemic and seasonal influenza viruses can be transmitted through aerosols and droplets, in which viruses must remain stable and infectious across a wide range of environmental conditions. Using humidity-controlled chambers, we studied the impact of relative humidity on the stability of 2009 pandemic influenza A(H1N1) virus in suspended aerosols and stationary droplets. Contrary to the prevailing paradigm that humidity modulates the stability of respiratory viruses in aerosols, we found that viruses supplemented with material from the apical surface of differentiated primary human airway epithelial cells remained equally infectious for 1 hour at all relative humidities tested. This sustained infectivity was …
Aerosol Microdroplets Exhibit A Stable Ph Gradient, Haoran Wei, Eric P. Vejerano, Weinan Leng, Qishen Haung, Marjorie R. Willner, Linsey C. Marr, Peter J. Vikesland
Aerosol Microdroplets Exhibit A Stable Ph Gradient, Haoran Wei, Eric P. Vejerano, Weinan Leng, Qishen Haung, Marjorie R. Willner, Linsey C. Marr, Peter J. Vikesland
Faculty Publications
Suspended aqueous aerosol droplets (<50 μm) are microreactors for many important atmospheric reactions. In droplets and other aquatic environments, pH is arguably the key parameter dictating chemical and biological processes. The nature of the droplet air/ water interface has the potential to significantly alter droplet pH relative to bulk water. Historically, it has been challenging to measure the pH of individual droplets because of their inaccessibility to conventional pH probes. In this study, we scanned droplets containing 4-mercaptobenzoic acid–functionalized gold nanoparticle pH nanoprobes by 2D and 3D laser confocal Raman microscopy. Using surface-enhanced Raman scattering, we acquired the pH distribution inside approximately 20-μm-diameter phosphate-buffered aerosol droplets and found that the pH in the core of a droplet is higher than that of bulk solution by up to 3.6 pH units. This finding suggests the accumulation of protons at the air/water interface and is consistent with recent thermodynamic model results. The existence of this pH shift was corroborated by the observation that a catalytic reaction that occurs only under basic conditions (i.e., dimerization of 4-aminothiophenol to produce dimercaptoazobenzene) occurs within the high pH core of a droplet, but not in bulk solution. Our nanoparticle probe enables pH quantification through the cross-section of an aerosol droplet, revealing a spatial gradient that has implications for acid-base–catalyzed atmospheric chemistry.
Physico-Chemical Characteristics Of Evaporating Respiratory Fluid Droplets, Eric P. Vejerano, Linsey C. Marr
Physico-Chemical Characteristics Of Evaporating Respiratory Fluid Droplets, Eric P. Vejerano, Linsey C. Marr
Faculty Publications
The detailed physico-chemical characteristics of respiratory droplets in ambient air, where they are subject to evaporation, are poorly understood. Changes in the concentration and phase of major components in a droplet—salt (NaCl), protein (mucin) and surfactant (dipalmitoylphosphatidylcholine)—may affect the viability of any pathogens contained within it and thus may affect the efficiency of transmission of infectious disease by droplets and aerosols. The objective of this study is to investigate the effect of relative humidity (RH) on the physico-chemical characteristics of evaporating droplets of model respiratory fluids. We labelled these components in model respiratory fluids and observed evaporating droplets suspended on …