# Presentation: 930170

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

- Yin-Nan Lee
- Atmospheric Sciences Division
- Brookhaven National Laboratory

- ASP Science Team Workshop Charleston, SC
- January 25, 2005

## 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.

## 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

_***Atmospheric Distributions***_

_***Physical and Chemical Properties***_

## 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)

_***Inorganic***_

_***Organic***_

## Major Classes of Aerosol Organic Compoundsand Their Sources

|  | Primary |  |  |  |  | Secondary |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  | Fossil fuel combustion (e.g.,vehicles) | Other anthropogenic processes (e.g., manufacturing, cooking) | Biogenic (e.g., vascular wax) and bio-organic (e.g., spores) | Biomass burning/wood burning | Soil | Gas-particle partiction(adsoprtion and Absorption) | Reactive condensation (e.g., acid catalyzed reactions) | In-Cloud processing |
| Alkanes, alkenes, alkanals, alkanoic acids and diacids |  |  |  |  |  |  |  | ? |
| Aromatics,
PAHs |  |  |  |  |  |  | ? | ? |
| Hopanes, steranes, UCM |  |  |  |  |  |  |  |  |
| Photochemical products, e.g., carbonyls |  |  |  |  |  |  |  |  |
| Sugar, polyols, ploysaccharides |  |  |  |  |  |  |  |  |
| levoglucosan |  |  |  |  |  |  |  |  |
| HULIS |  |  |  |  | ? |  | ? | ? |

## Specific Questions to be Addressed in this Research

| How much of the ambient aerosol is composed of organic material? | measure the total organic carbon, TOC |
| --- | --- |
| What fraction of the organics is water-soluble?  | measure the soluble organic carbon, WSOC |
| What is the formation rate of SOA? | measure TOC and WSOC as a function of time |
| Can the observed TOC and WSOC be explained by chemical models? 
 | Compare the formation of TOC and WSOC to that predicted by models in different environments, e.g., urban, power plant plumes and forested region |
| How much do TOC and WSOC contribute to aerosol light scattering, hygroscopicity, and CCN properties?  | Compare the calculated based on size distribution and chemical composition to the measured. |
| What are the sources and importance of HULIS? | Determine HULIS and its relationship to SOA |

## Research Plane

| Project | Approach | Goal |
| --- | --- | --- |
| Develop a TOC/WSOC technique | Based on PILS and Sievers TOC detector | LOD ~ 0.2 μgC m-3 |
|  | deployment on aircraft | Time resolution ~ 90 s |
|  | Removing nonpolar organics from sample | Quantifying WSOC as well as TOC |
| Bring an AMS on line | To compare the PILS-IC-TOC and AMS | Allows for cross calibration |
| Measure SOA formation rate | Field studies on the G1 (Mexico City, Houston) | Discern SOA formation mechanisms under different environments in terms of precursors and aerosol properties |
| Investigate the role of organics in aerosol optical/radiative effects | Collect simultaneous aerosol chemical and physical data during field studies | Understand the contributions of organics to light scattering and CCN properties |
| Characterize HULIS  | Based on filter sampling followed by liquid phase chromatography analysis | Determine the concentrations and possible sources and mechanisms |

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

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

## 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.

## Slide 11

## Deliverables

| Task | Specifics | Date |
| --- | --- | --- |
| Bring a new Aerodyne AMS on line | For laboratory study, initially | 9/05 |
| Construction of a PILS-IC-TOC instrument | LOD: 0.1 μg m-3 for inorganic ions; 0.2 μgC m-3 for TOC
Time resolution: 2.5 min | 9/05 |
| Calibration and comparison of PILS-IC-TOC and AMS | Using particles containing inorganic salts, soluble and insoluble organics in different combinations | 12/05 |
| Deployment of a PILS-IC on the DOE G1 | Measure inorganic ions during the 2005 ARM Field Experiment | 4-7/05 |

## Deliverables

| Task | Specifics | Date |
| --- | --- | --- |
| Deployment of the PILS-IC-TOC  | The 2006 Winter Mexico City Study | 1-4/06 |
| Analysis of Mexico City Data | Formation rate of SOA and relationships to sources and photochemistry | 9/06 |
| Deployment of the PILS-IC-TOC | The 2006 Summer Houston Study | 8-10/06 |
| Development of a WSOC measurement technique | Based on the PILS-IC-TOC using specific sorbents to remove the nonpolar organics | 12/06 |
| Intercomparison of the various TOC techniques | PILS-IC-TOC, AMS, and the OCEC on the ground | 5/07 |
| HULIS characterization | Macromolecule content and MW using the size exclusion chromatography technique | 9/07 |

## 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

## 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

*Polymeric substances comprising of alkanoic and benzenecarboxylic acids; molecular weight: 200 ~ 1000; similar to humic acids in UV, IR, NMR characters; possible mechanisms include in-cloud OH mediated reactions.*

## Aerosol concentrations (ng m-3) of OC, EC, polyhydroxylated, and mono- and dihydroxydicarboxylic acids during a LBA-CLAIRE wet season campaign in Balbina, Brazil, 2001. The percent carbon contributions to the OC are given in parentheses.

- Aerosol concentrations (ng m-3) of OC, EC, polyhydroxylated, and mono- and dihydroxydicarboxylic acids during a LBA-CLAIRE wet season campaign in Balbina, Brazil, 2001. The percent carbon contributions to the OC are given in parentheses.
***Claeys et al., Science, 303, 1173 (2004).***

## Kavouras et al., Environ. Sci. Technol., 33, 1028, 1999.

***Kavouras et al., Environ. Sci. Technol., 33, 1028, 1999.***

## Gas-Particle Partition of organic compounds – Absorption

***Liang et al., ES&T, 31, 3086 (1997)***

***e.g., Seinfeld and Pankow, Annu. Rev. Phys. Chem., 54, 121 (2003)***

## High vapor pressure aldehydes show major deviations

***Jang and Kamens, ES&T, 35, 3626 (2001).***

## -Pinene reaction products show significantly higher partition coefficients than predicted.

*Lee, Jang, and Kamens, Atmos. Environ., 38, 2597 (2004)*

- -Pinene reaction products show significantly higher partition coefficients than predicted.

## Acid catalyzed reactions of atmospheric carbonyls in aerosol particles –

***Jang et al., Science, 298, 814 (2002).***

## In-cloud formation of oxalic acid – 

**In-cloud formation of oxalic acid – **
***Warneck, Atmos. Environ., 37, 2423 (2003)***

## Principle of the Sievers TOC Analyzer

- Conductivity cell

- MEMBRANE MODULE

- MEMBRANE MODULE

## Calibration of the Sievers TOCD using Na2CO3 (left) and resorcinol (right)

- Calibration of the Sievers TOCD using Na2CO3 (left) and resorcinol (right)

## Slide 25