AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Predicting Ambient Aerosol Thermal Optical Reflectance OC, EC and TC Measurements from Infrared Spectra
ANN DILLNER, Satoshi Takahama, University of California, Davis
Abstract Number: 27 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract Organic aerosol functional group composition in aerosol samples has been measured using infrared spectroscopy (Ruthenburg et al., 2014, Takahama et al., 2013). One method for calibrating infrared spectra for functional group measurement is partial least squares regression (PLSR), a multivariate technique that relates spectral absorbances to the moles of functional groups on standards (Ruthenburg et al., 2014, Reff et al. 2007). The objective of this work is to demonstrate the feasibility of using infrared spectra of aerosol samples and PLSR to predict thermal optical reflectance (TOR) OC, EC and TC measurements of aerosols. Parallel quartz filter samples used for TOR analysis and PTFE filter samples used for infrared analysis from select sites in the IMPROVE network are used in the demonstration. A subset of samples is used to develop the calibration and the remaining samples are used to evaluate the calibration. Various scenarios for selecting the calibration and test sets are evaluated along with comparing two different PLS algorithms (PLS1 and PLS2) and using raw or baseline corrected spectra. The agreement between predicted and observed OC and EC compares well to the agreement between collocated samples analyzed by TOR.
Reff, A., B. J. Turpin, J. H. Offenberg, C. P. Weisel, J. Zhang, M. Morandi, T. Stock, S. Colome and A. Winer, 2007, A functional group characterization of organic PM2.5 exposure: Results from the RIOPA study. Atmospheric Environment 41(22): 4585-4598.
Ruthenburg, T.C., Perlin, P.C., Liu, V., McDade, C.E., Dillner, A.M., 2014, Determination of Organic Mass and Organic Mass to Organic Carbon Ratios by Infrared Spectroscopy with Application to Selected Sites in the IMPROVE Network. Atmospheric Environment 86, 47-57, http://dx.doi.org/10.1016/j.atmosenv.2013.12.034.
Takahama, S., Johnson, A., Russell, L.M., 2013, Quantification of Carboxylic and Carbonyl Functional Groups in Organic Aerosol Infrared Absorbance Spectra. Aerosol Science and Technology 47, 310–325, doi:10.1080/02786826.2012.752065