Institute for Atmospheric and Climate Science Berko Sierau

Institute for Atmospheric and Climate Science Berko Sierau Single Particle Chemical Characterization and Measurements of Cloud Condensation Nuclei Berko Sierau, Maria Martin ETH Zurich, Switzerland ASCOS Planning Workshop Landskrona, 8 th-10 th April 2008 ASCOS planning meeting, 8 th April 2008 IACETH

Institute for Atmospheric and Climate Science Berko Sierau Instrumentation I: Chemical Analysis and Size Online chemical characterization of individual aerosols using the Aerosol-Time-of-Flight Mass Spectrometer (ATOFMS, TSI-3800) Aerodynamic Sizing - Sample polydisperse aerosol - NOT a scanning technique - Determine size distribution of aerosol (250 nm – 3000 nm) • by composition • by time ASCOS planning meeting, 8 th April 2008 IACETH 2

Institute for Atmospheric and Climate Science Berko Sierau Instrumentation II: Chemical Analysis Time-of-Flight Mass Spectrometry - Positive and negative ion mass spectra of single particles - Complete mass spectra of each particle - Mass spectra indicate particle composition - Both non-volatile and semi-volatile compounds can be detected - Detection of refractory material (sea salt aerosol, soot) cp. to AMS - Non-quantitative measurement (parallel measurements of Aerodyne -MS is an important addition) ASCOS planning meeting, 8 th April 2008 IACETH 3

Institute for Atmospheric and Climate Science Berko Sierau Instrumentation III: Single Particle Mass Spectrometry Aerodynamic lens Sizing lasers (532 nm) Desorption/Ionization laser (266 nm) ASCOS planning meeting, 8 th April 2008 IACETH 4

Institute for Atmospheric and Climate Science Berko Sierau Instrumentation IV: Measurments of Cloud Condensation Nuclei Properties Measurement of CCN-active fraction of the ambient aerosol using the Cloud Condensation Nuclei Counter (CCNC; DMT, Boulder, USA) - Supersaturation range 0. 1 -2%, 30 second supersaturation change - CCN activation ratio and concentration measured as a function of water vapor saturation - CCN activation ratio and concentration measured as a function of particle diameter - CCN activation ratio and concentration of one particle diameter and at one supersaturation as a function of time (standard measurement procedure can be extended as a second CCNC will be provided) ASCOS planning meeting, 8 th April 2008 IACETH 5

Institute for Atmospheric and Climate Science Berko Sierau Instrumentation V: CCN Counter, Mode of Operation ASCOS planning meeting, 8 th April 2008 IACETH

Institute for Atmospheric and Climate Science Berko Sierau Open Questions / Discussion Operational mode of CCNC ? - Measurement of size-segregated CCN properties only possible if a DMA is employed upstream of the instrument (not provided by ETH) - Routine calibration of CCNC using DMPS system employed for standard size distribution measurements? - CCNC and IN chamber on common inlet as they share a CPC upstream of the instrument ASCOS planning meeting, 8 th April 2008 IACETH 7