Design and Evaluation of the Field-Deployable Electrostatic Precipitator with Superhydrophobic Surface (FDEPSS) with High Concentration Rate

Abstract

Here we report on further development of an electrostatics-based bioaerosol collector with high concentration rate. We developed a field-deployable version of the electrostatic precipitator with superhydrophobic surface (FDEPSS), which consists of two combined half-cylinder collection chambers and an integrated control box. The collector is made of a static dissipative material and each collection chamber features a 3.2 mm wide collection electrode. The round top part of each chamber contains eight carbon fiber ionizers arranged in two lines of four. The collected particles are removed by a 20 µL rolling water droplet. Sampler's components were integrated into a control box.The FDEPSS was tested with two bacterial species, Bacillus atropheus and Pseudomonas fluorescens bacteria, and one fungal spore, Penicillium chrysogenum for 10 and 60 min collection times and showed collection efficiency of ~70% at a sampling flow rate of 20 L min -1 . The use of a collecting water droplet of 20 µL per collection chamber achieved sample concentration rates approaching 0.5 × 10 6 min -1 . The FDEPSS was also tested against BioSampler (SKC Inc., Eighty Four, PA) and Button aerosol sampler (SKC Inc.) when sampling bioaerosols outdoors for 60 min. The samples were characterized based on the total airborne adenosine triphosphate (ATP) concentration, which was reported as relative luminescence units (RLU). The FDEPSS detected 5.1 × 10 5 RLU m -3 , while the BioSampler and the Button sampler showed 4.1 × 10 5 RLU m -3 and 8.7 × 10 5 RLU m -3 , respectively. Since ATP analysis can be performed with small sample volumes, and the FDEPSS captures particles into 20 µL of liquid, resulting in a high concentration rate, we show that this sampler can detect the presence of airborne microorganisms 40× faster than the BioSampler or Button aerosol sampler. This FDEPSS feature could be integrated into bioaerosol detection systems, especially where concentrations are low and time is critical.

Design and development of a self-contained personal electrostatic bioaerosol sampler (PEBS) with a wire-to-wire charger

“…One of the figures presented below compared the efficiencies determined by the two methods. In addition to collection efficiency, the sampler's concentration rate, R C (min ¡1 ), was calculated using the sampler's operational parameters as follows (Han and Mainelis 2008;Han et al 2010Han et al , 2015b:…”

“…Both microorganism species have been widely used in bioaerosol studies (Johnson et al 1994;Hill et al 1999;Nadkarni et al 2002). The bacteria were cultured in nutrient broth (Becton, Dickinson and Company, Sparks, MD, USA) for 18 h at 30 C as per our established protocol (Han et al 2015b). The cells were harvested by centrifugation at 7000 rpm (6140 g) for 5 min at 4 C (BR4, Jouan Inc., Winchester, VA, USA) and then washed four times with sterile DI water (Millipore Corp., Billerica, MA, USA).…”

“…The final liquid suspension was diluted with sterile DI water to obtain a target airborne cell concentration of »10 4 cells/L as determined by the Grimm OPC. P. chrysogenum was plated onto Sabouraud dextrose agar (Becton Dickinson Microbiology Systems, Cockeysville, MD, USA) and incubated at room temperature (approximately 26 C) for 7 days following an established protocol (Han et al 2015b). After incubation, about 3 mL of sterile deionized water was added to each plate of P. chrysogenum, and the spores were gently harvested from mycelium using a cell spreader.…”

Impact of sampling and storage stress on the recovery of airborne SARS-CoV-2 virus surrogate captured by filtration

“…The aerosolized viral particles were combined with a dry airflow, Q d (5 L/min) (Han et al 2015;Zhen et al 2013). The flow stream was passed through a 2-mCi Po-210 charge neutralizer (Amstat Industries Inc., Glenview, IL) to reduce aerosolization-imparted particle charges to Boltzmann charge equilibrium.…”

Application of ATP-based bioluminescence for bioaerosol quantification: Effect of sampling method

“…When analyzing bioaerosol samples, the amount of bioluminescence produced during the reaction between ATP and appropriate enzymes is proportional to the collected bioaerosol concentration (Karl, 1980). Thus, the method could be used as an indicator of total bioaerosol load in field or in situ studies (Han et al, 2015b; Lin et al, 2013; Park et al, 2014; Yoon et al, 2010). Some studies are strong correlation between ATP content in indoor air and concentration of culturable bacteria (Yoon et al, 2010).…”