AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Electrical Charges on Particles Generated by Combustion
Sergey A. Grinshpun, SHUANG GAO, Michael Yermakov, Tiina Reponen, University of Cincinnati
Abstract Number: 53 Working Group: Combustion
Abstract Electric charges acquired by aerosol particles during their generation affect the particle transport, sampling, filtration efficiency, and respiratory deposition. Therefore, information is needed about the particle charge distribution. While laboratory-generated aerosols, which are conventionally used for the evaluation of aerosol measurement instruments, air purification units and other devices, are usually charge-neutralized/equilibrated by radioactive sources, aerosol particles in the field often carry substantial electric charges. Aerosols generated by open-space combustion and by traffic emission have long been recognized as an environmental hazard, but not sufficiently well characterized, especially in regard to their particle charge distribution. In this effort, we deployed an Electric Low Pressure Impactor (ELPI, Dekati, Ltd., Kangasala, Finland) for measuring electric charges on particles aerosolized by burning materials such as paper, wood and plastic, as well as by emission from a diesel engine. For comparison, similar measurements were also performed with NaCl and KCl aerosols generated using a Collison nebulizer. Major differences were observed between the charge distributions of combustion-originated particles (including diesel) and salt particles. In the ultrafine range (<100 nm), the particles released from burning as well as diesel particles were essentially neutral while KCl and especially NaCl particle carried measurable negative charges. Larger combustion particles (>100 nm) were negatively charged with the charge increasing as the particle size increased. The salt particles changed their polarity from negative to positive as the size increased above 100 nm. The differences were attributed to the aerosolization process. The particle charge-to-volume ratio was utilized to interpret the experimental results. The measured charges were compared to the maximum acquirable electrical charges calculated using the diffusion charging model. The data obtained in this study are presently being used for assessing the efficiency of indoor air purifiers.
This effort was partially supported by the US Department of Housing and Urban Development, Grant OHHHU0027-14.