 |
|
|
|
|
Mary K. Gilles Lawrence Berkeley National Laboratory 1 Cyclotron Road, Mail Stop 6-2100 Berkeley, CA 94720 Tel: 510-495-2775 Fax: 510-495-2067 email: MKGilles@lbl.gov Direct measurements of the mixing state of black carbon are necessary for improved modeling of black carbon radiative properties. The technique to map near edge x-ray absorption fine structure spectroscopy (NEXAFS) onto single carbonaceous aerosol particles will be developed. Mapping techniques currently used in multicomponent polymer systems will be extended to investigate the distribution of black carbon in individual aerosol particles. The ultimate goal is determination of the distribution of black, organic and inorganic carbon along with nitrogen and oxygen functional groups with a spatial resolution of 35 nm. Chemical maps of the carbon will be used to determine the mixing state of the carbonaceous particles. For selected particles, metals (and their oxidation states) or sulfur spectra may also be acquired and mapped. The variation in NEXAFS spectra of atmospheric samples will also be measured. Studies on the variation of NEXAFS (C and O edges) spectra of atmospheric samples will be compared with black carbon surrogates (n-hexane soot, Palas soot etc.). Field samples are an important part of this project and will be provided by several collaborators. Collaborative participation in laboratory field studies (Pt. Reyes and MAX-Mex) are with Alex Laskin (PNNL) who will be performing TEM measurements. The results of this research will lead to soot characterization, determination of mixing states, and insight into atmospheric aging, improving our ability to model their radiative influence. [back to ASP ST Membership] |