Characterization of Aerosol Organic Matter: Detection, Formation, Optical and Radiative Effects

1. Characterization of Aerosol Organic Matter: Detection, Formation, Optical and Radiative Effects Yin-Nan Lee Atmospheric Sciences Division Brookhaven National Laboratory

2. Research Objectives To develop a real-time TOC measurement technique suitable for aircraft deployment that can also quantify the WSOC. To determine aerosol chemical composition, including TOC and WSOC, as well as inorganic ions during field campaigns. To investigate the relationships between TOC and WSOC and their precursors. To determine the rate of SOA formation and its connection to photochemical reactions of VOCs. To identify the mechanisms important to SOA formation, including the acid catalyzed reactions. To characterize the humic like substances (HULIS) in terms of size, sources and formation mechanisms. To evaluate the contributions of organic components to aerosols’ optical and radiative effects.

3. Knowledge of chemical composition is the key to understanding many aerosol properties Sources Formation mechanisms Size distributions Life times Light extinction Scattering absorption Hygroscopicity Size dependence on RH Cloud condensation nuclei property Air quality and health effects

4. Major Chemical Components of Ambient Aerosol Particles Sulfate, nitrate, phosphate, chloride Ammonium, sodium, potassium, calcium, magnesium Aluminum, cadmium, iron, lead, silicon Black carbon Alkanes, alkanols, alkanoic acids, diacids, ketoacids Polycyclic aromatic hydrocarbons (PAHs) Alkenes and aldehydes Pesticides/PCBs Polyols, carbohydrates Humic like substances (HULIS)

5. Major Classes of Aerosol Organic Compoundsand Their Sources

6. Specific Questions to be Addressed in this Research

8. Aerosol NH4 and SO4 concentrations and light scattering coefficient during a power plant plume study, 8/9/04, NEAX

9. Some aerosol properties observed during the 8/9/04 power plant plumes study, NEAX

10. Anticipated Output of Research Source identification of organics (in association with black carbon and VOC distributions). Formation mechanisms of SOC (absorption vs on-particle reactions). Contributions of organics to aerosol mass, hygroscopicity and light scattering. Effects to cloud condensation nuclei properties. Improved understanding of HULIS. Aid the interpretation of AMS data. Help to understand the OCEC measurement.

12. Deliverables

13. Deliverables

14. Relationships to Other ASP Projects Chemical composition: SO4, NO3, NH4, K, Ca, Mg, Na, Cl Formate, acetate, oxalate TOC, WSOC, HULIS Source Identification Process Evaluation Optical properties Scattering, absorption, and single scattering albedo CCN properties Size distribution – OPC, DMA Light scattering – Nephelometer Light absorption – Aethalometer f(RH) – based on, e.g., bsp CCN concentration Total carbon – OCEC VOC and photochemistry Aerosol optical depth Air back trajectories Meteorological data, e.g., T, RH, wind directions and speed

15. Humic Like Substances (HULIS) Sampling: Filter based Extraction into an aqueous solution Identification: Size exclusion chromatography using sephadex packing Using either UV absorption or refractive index detectors Background information: OCEC PILS-TOC Air back trajectory to identify the role of cloud processing

23. Principle of the Sievers TOC Analyzer