AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Brown Carbon Formation from Aqueous-phase Syringol under Dark Conditions
JIAN XU, V. Faye McNeill, Columbia University
Abstract Number: 665 Working Group: Aerosol Chemistry
Abstract Aerosol brown carbon (BrC) dominates aerosol light absorption at wavelengths up to 500 nm and may contribute significantly to climate forcing. Recent studies reported that biomass burning not only provides a primary source for BrC (Liu et al., 2014) but also serves as an important secondary formation pathway under varying conditions (Chang et al., 2010). More information on the formation mechanisms and light absorbing properties of secondary BrC are needed.
We performed laboratory experiments using syringol, which is a representative model phenolic compound emitted from wood burning, in bulk concentrated salt solutions mimicking aqueous tropospheric aerosol particles. We observed the formation of light-absorbing organic products (brown carbon) within 12 hours under dark conditions. We present kinetic data and propose a mechanism, and products will be discussed. Our results provide new insights into the evolution of aerosol optical properties during aging.