Abstract View
Comparison of Particle Phase Data from FIGAERO CIMS and LTOF-AMS from Formation of Biogenic Particles in the CERN CLOUD Chamber
BRANDON LOPEZ, Mingyi Wang, The CLOUD Collaboration, Neil Donahue, Carnegie Mellon University
Abstract Number: 530
Working Group: Instrumentation and Methods
Abstract
The formation of particles by highly oxygenated molecules from the ozonolysis of biogenic precursors has been observed in the controlled environment of the CERN CLOUD chamber under conditions of the free troposphere. The composition and properties of particles in air masses depend on the formation conditions but can also be influenced by changing conditions as the particles are transported through the atmosphere. Here we present results from pure biogenic nucleation at constant temperatures from +5 to -50 oC at various values of relative humidity (RH). We explore the particle composition by comparing real-time data from two mass spectrometers using positive matrix factorization (PMF). The aerosol mass spectrometer (AMS) quantitatively measures the bulk composition of particles, while the Filter Inlet for Gases and AEROsols (FIGAERO) with an iodide chemical ionization mass spectrometer can provide aerosol molecular information. The bulk AMS data depend strongly on temperature but weakly on RH; however, PMF analysis of the FIGAERO data reveals that the particle composition is significantly different at different RH, despite the similar AMS spectra. The two data sets are thus complementary, suggesting that bulk aerosol properties may remain relatively unchanged even as the overall particle composition is influenced by the presence of water.