1. Particulate composition James Allan, Paul Williams, Mike Flynn, Claire Martin, Hugh Coe & Martin Gallagher University of Manchester & NCAS Eiko Nemitz & Gavin Pillips CEH Edinburgh

2. Rationale The chemical composition of particulates affects its toxicity The composition also has implications for acid deposition and climate forcing Studying the detailed composition gives important insights into sources and processes of particulates in the urban atmosphere

3. Measurement sites (REPARTEE I & II) Regent’s Park BT Tower

4. Instruments used Filter samplers –Offline analysis of inorganic ions ECN Gradient System for Reactive Aerosols and Gases with Online Registration (GRAEGOR) –Online analysis of inorganic ions and soluble gases Aerodyne Aerosol Mass Spectrometer (AMS) –Online analysis of nonrefractory particulates.

5. GRAEGOR Thomas et al., Environ. Sci. Technol., 43, 1412–1418, 2009

6. DeCarlo et al., Anal. Chem., 78, 8281-8289, 2006; Canagaratna et al., Mass Spectrom. Rev., 26, 185-222, 2007. AMS

7. REPARTEE-I PM10 Composition BT Tower (GRAEGOR)

8. REPARTEE-II PM 10 Composition BT Tower (GRAEGOR)

9. REPARTEE-I Aerosol Components BT Tower Bold: GRAEGOR PM 10 Fine: AMS NR-PM 1 Steps: Filter PM 10

10. Filter vs. GRAEGOR  The filter loses 50% of fine NH 4 NO 3 during peak concentrations.

11. AMS Comparison REPARTEE-II

12. Organics (AMS) McFiggans et al., Faraday Discuss., 130, 341-362, 2005.

13. PMF analysis Paatero, Chemometr. Intell. Lab., 37, 23-35, 1997; Lanz et al., Atmos. Chem. Phys., 7, 1503-1522, 2007; Ulbrich, et al., Atmos. Chem. Phys., 9, 2891-2918, 2009.

14. Types: –Oxygenated (OOA) –Hydrocarbon-like (HOA) –Cooking (COA) –Solid fuel (SFOA) Allan et al., Atmos. Chem. Phys., 10, 647-668, 2010.

16. Cooking Aerosols Mohr et al. (2009) Heated cooking oil baths Katrib et al. (2004) and Alfarra (2004)

17. Diurnal profiles

18. Grid-scale emission factors REPARTEE 1 (relative to NO x )Manchester (relative to CO) HOA (µg m -3 ) SFOA (µg m -3 ) CO (ppm) HOA: 31.6 µg m -3 ppm -1 Mass emission ratio (MER): 0.026 (as NO) HOA: 20.5 µg m -3 ppm -1 MER: 0.018 SFOA: 24.7 µg m -3 ppm -1 MER: 0.021

19. Summary & Conclusions Chemical composition of particulates was measured in multiple locations with multiple instruments during the REPARTEE experiments The use of online instrumentation gives much better time resolution in the data and avoids many problems associated with offline analysis Analysis of the high-resolution composition data sheds light on many urban aerosol sources and processes This is further enhanced by the use of multiple measurement sites, instruments and data collection methods Stay tuned for the next presentation…

20. Acknowledgements This work was partly supported by the NERC CityFlux project (ref. NE/B504865/1) and the BOC Foundation. C. L. Martin was supported by a NERC studentship (ref. NER/S/A/2005/13219) Many thanks to The Royal Parks and BT for access to the measurement sites