AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Source Apportionment of PM10, PM2.5, PM1 Organic Aerosol Using Aerosol Mass Spectrometry
ANDRE PRÉVÔT, Carlo Bozzetti, Imad El Haddad, Robert Wolf, Emily Bruns, Adela Krepelova, Kaspar Daellenbach, Jay Slowik, Urs Baltensperger, Paul Scherrer Institute
Abstract Number: 139 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract The Aerodyne aerosol mass spectrometer offers quantitative real-time measurements of the size-resolved chemical composition of bulk non-refractory submicron aerosol (Organic aerosol (OA), nitrate, ammonium, sulphate, chloride). To extend the AMS ability to measure size-fractioned mass spectra, we explored the application of laboratory AMS measurements of aerosol filter samples. Such methodology based on offline sampling offer the separation of particles in discrete size ranges, including supermicron particles (PM10). Moreover the high cost and the complex maintenance of the AMS significantly limit the spatial coverage of this instrument and the collection of long-term data. These restrictions motivated us to investigate the application of AMS analysis to filter samples, which are easy and cheap to collect and store. The approach involves a water extraction of the particulate matter from quartz filters by sonication and subsequent nebulisation of the aerosol extract into the AMS. The OA extraction efficiency has been evaluated by comparison with AMS online measurements performed during the same period, estimated as 80% on average for the PM2.5. Method detection limits are estimated for organic aerosol, NO3-, SO42-, and NH4+ as 410 mgL-1, 210 mgL-1, 260mgL-1, and 200 mg L-1, respectively. Here, we present the application of the offline AMS approach to PM1, PM2.5 and PM10 filter samples collected at a rural site in Switzerland during summer and winter. Differences in aerosol fingerprints across particle sizes are examined and results suggest a significantly different composition of coarse particles with higher contribution from fragments that are most probably related to carbohydrates (e.g. m/z 29 and 60). Size-resolved statistical ME-2 analyses applied to these measurements will be discussed and compared with online AMS measurements to identify the contribution of primary biological particles and other components.