AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Constraining Particle Bounce in an Impactor
ADAM BATEMAN, Scot Martin, Harvard University
Abstract Number: 235 Working Group: Instrumentation and Methods
Abstract Recently, it has been inferred from measurement of particle bounce in an impactor that secondary organic aerosol (SOA) particles are solid. This is based on the assumption that solid particles will bounce during impaction, while liquid particles will not. This assumption is investigated using custom made impactors designed to study particle bounce. During impaction, many particles have enough inertia to not only impact with the plate, but also to escape from the plate i.e. “bounce”. It has been observed by many early impaction studies attempting to quantify the mass fraction of aerosols in the atmosphere and laboratory that solid particles will bounce in an impactor while liquid particles will not. However, these observations are qualitative at best. A wide range of bounce behavior has been observed as a function of particle composition and relative humidity (RH), warranting further research into the bounce behavior of particles in an impactor. A variety of particles, both solid and liquid, as well as SOA particles generated from a flow tube and the Harvard Environmental Chamber (HEC) were studied as a function of RH in an attempt to constrain the assumption that if a particle bounces during impaction then it must be a solid, while if it does not bounce, then it is a liquid.