Characterization of reaerosolization from impingers in an effort to improve airborne virus sampling

Abstract

Aims: To assess the impact of reaerosolization from liquid impingement methods on airborne virus sampling. Methods and Results: An AGI‐30 impinger containing particles [MS2 bacteriophage or 30‐nm polystyrene latex (PSL)] of known concentration was operated with sterile air. Reaerosolized particles as a function of sampling flow rate and particle concentration in the impinger collection liquid were characterized using a scanning mobility particle sizer. Reaerosolization from the impinger was also compared to that from a BioSampler. Results show that reaerosolization increases as flow rate increases. While the increased particle concentration in the impinger collection liquid leads to an increase in the reaerosolization of PSL particles, it does not necessarily lead to an increase in the reaerosolization of virus particles. Reaerosolization of virus particles begins to decrease as the particle concentration in the impinger collection liquid rises above 106 PFU ml−1. This phenomenon results from aggregation of viral particles at high concentrations. Compared with micron‐sized particles, nanosized virus particles are easier to aerosolize because of reduced inertia. Reaerosolization from the BioSampler is demonstrated to be significantly less than that from the impinger. Conclusions: Reaerosolization from impingement sampling methods is a mode of loss in airborne virus sampling, although it is not as significant a limitation as the primary particle size of the aerosol. Utilizing a BioSampler coupled with short sampling periods to prevent high accumulative concentrations can minimize the impact of reaerosolization. Significance and Impact of the Study: This study confirms reaerosolization of virus particles to be a mode of loss in impingement sampling and identifies methods to minimize the loss.

Inactivation of Aerosolized Viruses in Continuous Air Flow with Axial Heating

“…In addition, the data points representing viruses in liquid may signify individual dispersed MS2 virions. In contrast, the MS2 aerosols generated by the Collison nebulizer are likely contained aggregates and/or particles covered by residue from the nebulization suspension (Eninger et al 2009;Hogan et al 2005;Riemenschneider et al 2010). These factors, in principle, can enhance resistance of aerosolized viruses to environmental stress, including heat.…”

Standardization of a Protocol for Quantitative Evaluation of Anti-Aerosolized Influenza Virus Activity by Vapors of a Chemically-Characterized Essential Oil Blend

“…aerosolized virus, that will be subjected to viability evaluation after contact with the antiviral vapors [6][7][8]. The construction of impingers by many previous investigators required a pulverization chamber to aerosolize the viral particles and to provide contact with vapors of experimental air sanitizers, connected to a collection flask, which in turn is connected to a vacuum pump, creating a converged environmental air stream that delivers the aerosolized particles to a liquid phase in the collection flask [9][10][11][12]. The collected virus in the liquid phase will be tested for its viability by propagating it in appropriate cell culture line or in chicken embryos [13].…”

Evaluation of the Performance of Iodine-Treated Biocidal Filters Under the Influence of Environmental Parameters

“…The size-classified particles were collected in the BioSampler. To minimize any loss in collected viruses to long sampling times and to reaerosolization, a flow rate of 4.5 Lpm and sampling time of 5 min were applied (Riemenschneider et al 2010). The number of viable viruses collected in BioSamplers was enumerated by a single-layer bioassay.…”

“…The data reported by Hogan et al (2005) agree well for smaller (30 nm) and larger particles (300 nm) tested. Because a 4.5-Lpm flow rate was employed for further tests to avoid reaerosolization (Riemenschneider et al 2010), collection efficiencies of 12%, 8%, 6%, 4%, 4%, 6% and 7% for 30-, 60-, 90-, 120-, 150-, 180-and 230-nm particles, respectively, were applied as a correction factor for other tasks. Figure 7 displays number-based PSDs for aerosols generated from MS2 suspensions in DI water, BE and AS under three RHs.…”