AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Multidimensional Characterization of Individual Aerosols Particles
ALLA ZELENYUK, Dan Imre, David Bell, Jacqueline Wilson, Josef Beranek, Pacific Northwest National Laboratory
Abstract Number: 605 Working Group: Single Aerosol Particle Studies - Techniques and Instrumentation
Abstract Small, ultrafine and fine, particles are ubiquitous in natural and human-made environments, playing an important role in many areas that have direct impact on our lives. The behavior and impacts of small aerosol particles depends on a number of their physical and chemical properties, many of which are strongly coupled. Traditional particle characterization approaches rely on a number of independent measurements that average over a heterogeneous mixture of particles of different properties and later attempt to draw correlations between all observables. As a result, major differences between individual particles are often overlooked.
We will present our unique approach to measure simultaneously, in-situ and in real-time, a large number of individual particles attributes, using our single particle mass spectrometers, SPLAT II and miniSPLAT, in combination with other instruments. This multidimensional single particle characterization yields comprehensive, quantitative analysis of individual particles with ultrahigh sensitivity, sub-nanometer precision and accuracy, and with high temporal resolution.
We will demonstrate the utility of this approach to characterize secondary organic aerosol, metal nanoparticles, and combustion-related particles. We will illustrate how we characterize in situ and in real time individual particle size, mass, density, chemical composition, morphology, phase, chemical diffusivity, viscosity, porosity, number concentration, size distribution. We obtain information on different aspects of particle shape, which include particle asphericity, asymmetry, and dynamic shape factors, in the transition and free-molecular regimes, and fractal dimension. We also measure particle hygroscopicity, particle activity as cloud condensation and ice nuclei, size-dependent evaporation kinetics, and rates of heterogeneous reactions. In addition, we will present a new approach to identify and separate particles of different shapes.
Most importantly, we will show that the very same instruments can be used in the laboratory and be deployed in the field, including onboard aircraft.