200 likes | 373 Vues
This presentation highlights the intricate chemical composition of urban particulate matter and its implications for toxicity, acid deposition, and climate effects. Conducted at various sites in Manchester, the REPARTEE experiments utilized advanced techniques such as online analysis with the GRAEGOR and Aerodyne AMS, revealing significant insights into aerosol sources including cooking and solid fuels. The study underscores the importance of real-time data collection for understanding urban aerosol processes and emissions, supported by collaborations with the NERC CityFlux project.
E N D
Particulate composition James Allan, Paul Williams, Mike Flynn, Claire Martin, Hugh Coe & Martin Gallagher University of Manchester & NCAS Eiko Nemitz & Gavin Pillips CEH Edinburgh
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
Measurement sites(REPARTEE I & II) Regent’s Park BT Tower
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.
GRAEGOR Thomas et al., Environ. Sci. Technol., 43, 1412–1418, 2009
AMS DeCarlo et al., Anal. Chem., 78, 8281-8289, 2006; Canagaratna et al., Mass Spectrom. Rev., 26, 185-222, 2007.
REPARTEE-I Aerosol Components BT TowerBold: GRAEGOR PM10 Fine: AMS NR-PM1 Steps: Filter PM10
Filter vs. GRAEGOR The filter loses 50% of fine NH4NO3 during peak concentrations.
Organics (AMS) McFiggans et al., Faraday Discuss., 130, 341-362, 2005.
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.
Types: • Oxygenated (OOA) • Hydrocarbon-like (HOA) • Cooking (COA) • Solid fuel (SFOA) Allan et al., Atmos. Chem. Phys., 10, 647-668, 2010.
Cooking Aerosols Heated cooking oil baths Mohr et al. (2009) Katrib et al. (2004) and Alfarra (2004)
Grid-scale emission factors REPARTEE 1 (relative to NOx) Manchester (relative to CO) CO (ppm) SFOA (µg m-3) HOA (µg m-3) 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
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…
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