Secondary Organic Aerosol Formation from Glycol Ethers

REINA BUENCONSEJO, Haroula D. Baliaka, Paul Wennberg, John Seinfeld, California Institute of Technology

     Abstract Number: 563
     Working Group: Aerosol Chemistry

Abstract
Recent work indicates the growing importance of volatile chemical products (VCPs), particularly as air pollution regulations drive down the contribution of vehicular-based emissions. It is important to characterize the effects of VCPs on atmospheric secondary organic aerosol (SOA) and its formation to better resolve discrepancies between SOA observations and models. This work looks at ethoxyethanol and butoxyethanol, VCPs used as industrial solvents, cleaning supplies, and paints.

Using a 19 m³ environmental smog chamber, SOA yields of glycol ethers, including ethoxyethanol and butoxyethanol, are probed over a range of NO mixing ratios and RO₂ bimolecular lifetimes to better understand SOA formation as a function of a variety of different environmental conditions. Gas-phase chemistry leading up to SOA formation is analyzed using a CF₃O^- chemical ionization mass spectrometer (CIMS).

In low-NOx conditions, the unimolecular hydrogen shift reaction to the ethoxyethanol peroxy radicals is shown to be important, making this autoxidation competitive with bimolecular pathways. This work addresses glycol ethers as a chemical class of VCPs. In particular, this work is relevant to urban environments like the Los Angeles Basin where NO_x levels and other vehicular emissions continue to decrease but where VCPs are continuing to play an important role in air quality.