1. CHEMICAL COMPOSUTION OF ORGANIC AEROSOL EXPLORED BY TD-PTR-MS Rupert Holzinger, Joseph Timkovsky, Beatriz Oyama, Niels van Elst, Patrick Schlag, Ulrike Dusek Institute for Marine and Atmospheric Research (IMAU), Utrecht University, Netherlands

2. Outline  The TD-PTR-MS instrument  Field Campaigns, Cabauw & CalNex  Organic Aerosol (OA) on Filter Samples  Urban OA in Sao Paulo, Brazil  OA across the Atlantic Ocean

3. The TD-PTR-MS: (Thermal-desorption Proton-transfer- reaction Mass-spectrometer) * Sensitivity * * Quantitative * * detects large fraction of organics *

4. Operation at the LA site, May 15 – June 15, 2010. Los Angeles Field Studies: Calnex & Cabauw © KNMI

5. Operation in the field  Cycling repeated every 90 min  Aerosols background every other run

6. Hundreds of organic (and a few inorganic) aerosol species are typically detected

7. Example timelines, different thermograms

8. Comparison with AMS at Cabauw, 2012 Good correlation between PTR-MS and ToF-AMS (r 2 =0.77), but PTR-MS only sees ~10-20 % of ToF-AMS mass:  Was also seen in previous campaigns (~ 30 % compared to AMS in 2008 and 2009)  PTR-MS had a bad MCP and could not measure masses > 250 properly

9. Comparison with AMS during CalNex

10. Correlation with OA-coponents (AMS-PMF), CalNex 2010

11. Results Correlation Analysis AMSPTR OA100160 HOA-ions1647 LVOOA-ions2264 Nitrogen concentration [ng/m3]: SV-OOA rejuvenating during daytime! More Nitrogen than expected.

12.  Organic Aerosol (OA) on Filter Samples Organic Aerosol on Filter Samples

13. 561011121315 Cabauw, NL, Feb/March 2011 Filter & In Situ

14. The comparison of in situ and filter measurements of aerosols with PTR-MS Points: background is subtracted; masses are binned into groups, binsize is 20 Da; data for the temperature range 150-350C are summed up 1-day filters2-day filters3-day filters

15. OA study in Sao Paulo, Brazil Janio Quadros Tunnel – inside the city LIGHT FLEET Rodoanel Tunnel – outside the city HEAVY FLEET Institute of Astronomy, Geophysics and Atmospheric Sciences University of Sao Paulo

16. Source signatures

17. Ambient OA, Sao Paulo, Brazil

18. OA during S/N Atlantic transect April/May 2010

19. 163 masses found Analysis of the Europe plume with the NH as background signal

20. Analysis of the NH background with the SH as background signal 7 ions found

21. Analysis of the SH Plume with the SH as background signal 355 ions found

22. Conclusions  TD-PTR-MS is a strong analytical tool, complementary to other techniques.  Surprising findings: (i) Rejuvenation of OA during daytime, (ii) high Nitrogen content  Reasonable agreement with AMS, SMPS etc.  Analysis of filter samples provides new opportunities Acknowledgements Funding: ACTRIS, NOW, NSF Thanks to colleagues from: University of Sao Paulo, Brazil; Univesity of California at Berkeley, University of Colorado, USA; Polarstern, Forschungszentrum Jülich, Germany; CESAR consortium, Netherlands.

26. Example for aerosol background:  Inlet A sampled ambient air  Inlet B sampled ambient air through Teflon filter