AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Investigation of the Chemical Aging and Absorption of Carbonaceous Aerosol from Wood Fires
ANTONIOS TASOGLOU, Spyros Pandis, Carnegie Mellon University
Abstract Number: 159 Working Group: Aerosol Chemistry
Abstract Smog chamber experiments were conducted to investigate the chemical and physical transformations of organic aerosol (OA) of biomass burning emissions exposed to OH radicals. A major focus of the study was the effect that chemical aging has on the absorption by the corresponding particles. The chemical processing of biomass burning OA results in the condensation of additional material on the initial particles and chemical changes of the OA. These changes can enhance the absorption of solar radiation by the biomass burning black carbon (BC). In our experiments we investigated emissions from yellow pine wood burning. The chemical aging of the biomass burning emissions was promoted by the production of hydroxyl radicals by three different sources: (1) HONO photolysis, (2) HOOH photolysis and (3) dark OH formation via ozone-alkene reaction. In the first case the experiments took place under high NOx conditions while in the other two under high NOx. Experiments were also conducted under low and high relative humidity conditions. A Soot Particle Aerosol Mass Spectrometer (SP-AMS) was used for the chemical characterization of the particles. For the study of the absorption of black carbon, we used a suite of instruments including an aethalometer and a green and a blue photoacoustic extinctiometer (PAX). A thermodenuder was used to characterize the changes of the particle volatility with chemical age. The changes in particle mass concentration, chemical composition, volatility, and absorption will be discussed.