Improving the collection efficiency of the liquid impinger for ultrafine particles and viral aerosols by applying granular bed filtration

Abstract

a b s t r a c tLiquid impingers are utilized to collect bioaerosols for many advantages, such as avoiding dehydration of biological agents. However, many previous studies have reported that the liquid impingers are surprisingly inefficient for the collection of ultrafine bioaerosols, with collection efficiencies o 30%. In the present work, we have successfully improved the collection efficiency of the liquid impinger (AGI30) to as high as 99% for particles in the size range of 20-400 nm with the aid of packed glass beads. We also systematically investigated the effects of influential factors on the collection efficiency. These factors include the volume of the sampling liquid (0, 20 and 30 mL), depth (0, 7 and 10 cm) of packed glass beads and sampling flow rate (4, 6 and 8 liter per min, lpm). According to our experimental results, increasing the depth of packed glass beads and the volume of sampling liquid can enhance the collection efficiency. Also, decreasing the sampling flow rate can increase the collection efficiency and reduce the loss of sampling liquid. For the sampling of viable MS2 phages, the collection efficiency of AGI30 sampler with packed glass beads is much higher than that without packed glass beads. Conclusively, this study validates that the granular bed filtration can enhance the collection efficiency of liquid impingers for submicron and ultrafine particles and viral aerosols.

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

“…The significant economic losses in domestic poultry and other animals, due to H9N2 and other subtypes such as the H5 and H7, resulted in development of related vaccines [3]; The inclusion of such vaccines in control programs created an immune pressure in the host against these viruses, that led to emergence of escape mutants with higher pathogenicity on both humans and vaccinated animals [4]. 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].…”

Effect of selected sampling media, flow rate, and time on the sampling efficiency of a liquid impinger packed with glass beads for the collection of airborne viruses

“…To enhance its collection efficiency for viral particles, we packed the AGI-30 sampler with glass beads (3 mm diameter), as shown in Fig. 1 a (Yu et al 2016 ). The manufacturer of these 3-mm glass beads (borosilicate glass) is Boeckel Co. (GmbH Co.) (BOECO Germany).…”

“…The collection efficiency of impingers depends on the aerodynamic diameters of airborne particles, and the main sampling mechanisms include inertial impaction, diffusion, and centrifugation (Yu et al 2016 ; Tseng and Li 2005 ; Terzieva et al 1996 ). However, the minimum cutoff size of particles was 300 nm for commercial impingers and showed very low collection efficiency (10–20%) for particles smaller than 100 nm (Hogan et al 2005 ).…”

“…Our previous studies have demonstrated that using a granular bed can enhance the performance of the all-glass impinger 30 (AGI-30), with a very high collection efficiency (> 98%) for particles of 20–500 nm (Yu et al 2016 ). However, many factors, such as relative humidity (RH), temperature, re-aerosolization, sampling media, sampling time, and sampling flowrate, could affect the collection efficiency and recovery of viruses (Verreault et al 2008 ).…”

Why respiratory viruses or bacteria have the highest probability to be deposited in the respiratory tract in flu seasons

“…The most techniques have the collection efficiencies <30% for nanosized aerosols (see review in (Yu et al, 2016)). It is dramatically small and, due to this, we can't talk with certainty in present time about the full picture of spreading of infections via ultrafine bioaerosols.…”