AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Particle Mass Concentration Determined from Single-Particle Mass Spectrometry Number Concentrations: Stability of Number Scaling Factors over Multiple Seasons
LISA AU, Aurora Janes, Ernesto Polania-Gonzalez, Jumaanah Flowers, Elizabeth Grubb, Deborah Gross, Carleton College
Abstract Number: 667 Working Group: Instrumentation and Methods
Abstract Single-particle mass spectrometers provide detailed information about the number-concentration, chemical composition and mixing state of individual aerosol particles. Procedures exist to convert the number-concentration to mass-concentration, based upon calibrating the data for particle transmission losses, and assuming an average particle density or composition-dependent densities. These methods have allowed the determination of total mass concentration of the sampled aerosol, and have been used to predict the mass concentration of different observed particle types, in ambient experiments. We have applied these methods to reproduce the total PM2.5 mass concentration in the vicinity of Northfield, MN and to apportion mass to different particle types identified through K-means clustering. Here we test this approach to reconstructing the PM2.5 mass concentration using single-particle mass spectrometry data acquired over four seasons, giving us the ability to examine the applicability of one set of scaling factors to an aerosol composed of differing particle sources and sampled under vastly different ambient conditions. Results for the seasonal variation of the particle types observed, and the reliability of the number- to mass-concentration scaling with a variety of particle-density selections, will be presented.