Experimental Investigation on Aerosolized Bacteria Mitigation Using Multiple DBD Plasma Sheets

Aerosolized bacteria mitigation finds many medical applications [1] - [2] . Continuing on our research in bacteria mitigation [3] , a new experimental rig is designed that incorporates two DBD plasma torches to expose E.coli/K-12-bacteria rich aerosols to helium plasma sheets. Our DBD plasma generator generates a plasma sheet (H=2.5cm, L=5cm, t=2mm). A small fraction of nitrogen was added to make the sheet more stable and to acquire higher nitrogen/oxygen reactive species that play a vital role in mitigating bacteria. An ultrasonic nebulizer was used to generate about 10 microns (D50) aerosols. Emission spectroscopy was performed to obtain information on nitrogen second positive system and SECAIR was used to extract information on plasma excitation, rotational, and vibrational temperatures. Helium plasma jets were found to impact the penetration of aerosols through the plasma region. This limitation was overcome by incorporating an extraction fan near the agar plates where aerosols were collected. A laser sheet was used to image the aerosols to ensure their passage through the plasma region. Enumeration of bacterial colonies (CFU) was used to ensure the accuracy of results. Bacterial colonies were measured as a function of the plasma operating conditions. Detailed final results will be presented in the conference.