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Browsing by Author "Tiwari, Andrea J."

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    Influenza Virus Infectivity Is Retained in Aerosols and Droplets Independent of Relative Humidity
    Kormuth, Karen A.; Lin, Kaisen; Prussin, Aaron J. II; Vejerano, Eric P.; Tiwari, Andrea J.; Cox, Steve S.; Myerburg, Michael M.; Lakdawala, Seema S.; Marr, Linsey C. (Oxford University Press, 2018-06-07)
    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 observed in both fine aerosols and stationary droplets. Our data suggest, for the first time, that influenza viruses remain highly stable and infectious in aerosols across a wide range of relative humidities. These results have significant implications for understanding the mechanisms of transmission of influenza and its seasonality.
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    Nanoparticles in road dust from impervious urban surfaces: distribution, identification, and environmental implications
    Yang, Yi; Vance, Marina; Tou, Feiyun; Tiwari, Andrea J.; Liu, Min; Hochella, Michael F. Jr. (Royal Society of Chemistry, 2016-05-24)
    Nanoparticles (NPs) resulting from urban road dust resuspension are an understudied class of pollutants in urban environments with strong potential for health hazards. The objective of this study was to investigate the heavy metal and nanoparticle content of PM2.5 generated in the laboratory using novel aerosolization of 66 road dust samples collected throughout the mega-city of Shanghai (China). The samples were characterized using an array of techniques including inductively-coupled plasma mass spectrometry, aerosol size distribution measurements, and scanning and transmission electron microscopy coupled with elemental characterization and electron diffraction. Principal metal concentrations were plotted geospatially. Results show that metals were generally enriched in aerosolized samples relative to the bulk dust. Elevated concentrations of metals were found mostly in downtown areas with intense traffic. Fe-, Pb-, Zn-, and Ba-containing NPs were identified using electron microscopy, spectroscopy, and diffraction, and we tentatively identify most of them as either engineered, incidental, or naturally occurring NPs. For example, dangerous Pb sulfide and sulfate NPs likely have an incidental origin and are also sometimes associated with Sn; we believe that these materials originated from an e-waste plant. Size distributions of most aerosolized samples presented a peak in the ultrafine range (<100 nm). We estimate that 3.2 ± 0.7 μg mg−1 of Shanghai road dust may become resuspended in the form of PM2.5. Aerosolization, as done in this study, seems to be a very useful approach to study NPs in dust.