A Miniature Probe for Instantaneous Aerosol Mobility Sizing

Atmospheric nucleation events inject large numbers of ultrafine particles into the air, some of which grow sufficiently large to affect the formation and characteristics of clouds. Yet widespread monitoring of these events is limited by the complexity, cost and size of available instrumentation. The miniature condensation particle counter of this project utilizes an innovative approach to measure the total number concentration of all particles larger than ~3 nm, and the activation size spectra of the smallest 3-10nm) of these. The approach combines aspects of existing technology in a new way to provide a compact instrument with a rapid response. In Phase I, we will test the critical aspects of this new approach through detailed modeling and experiment. Finite element numerical modeling will be used to define the parameters of the system, and guide the configuration of a prototype test cell.This prototype will be designed, fabricated and tested. It will be evaluated using laboratory-generated, monodisperse particles, and as well as ambient particles. Comparison will be made to a newly released commercial 2-nm cut-point benchtop condensation particle counter, that will serve as reference. This ultrafine particle counter would aid DOE’s research studies, and atmospheric aerosol research generally. More significantly, a lower cost version of the instrument is quite feasible. This would enable deployment on commercial flights, to provide routine measurements aloft. It would be useful for epidemiology studies, to assess health affects associated with proximity to ultrafine particle sources. It could find application in industry as a tool for monitoring ventilation in indoor spaces.