Understanding the Effect of NOx on the Secondary Organic Aerosol Formation from Phenolic Compounds from Biomass Burning

DAVID PANDO, Magesh K. Mohan, Rodney J. Weber, Nga Lee Ng, Georgia Institute of Technology

     Abstract Number: 244
     Working Group: Aerosol Chemistry

Abstract
As the world moves towards cleaner energy and the effects of global warming worsen, biomass burning has taken a larger fraction of the carbon emissions to the atmosphere and that fraction is expected to keep growing. Phenolic compounds account for a large portion of the volatile organic compounds (VOC) that are emitted to the atmosphere from biomass burning and their oxidation in the atmosphere can result in the formation of secondary organic aerosols (SOA). However, the processing of phenolic compounds and their oxidation products in the presence of NOx (which is emitted during biomass burning) is not well characterized. In this work, the effect of NOx on SOA formation from phenolic compounds is studied in the Georgia Tech Environmental Chamber (GTEC) facility. The VOC, other gases, and particles in the chamber are monitored by on-line instruments such as GC-FID, NOx monitor, ozone monitor, SMPS, FIGAERO-CIMS, and AMS. In our experiments we find that NOx enhances the SOA formation from phenolic compounds. For about 75 ppb of reacted phenol, the SOA yield (aerosol formed/VOC reacted) in high NOx­ experiments is approximately 55% to 60%, compared to the experiments conducted without NOx injection where the SOA yield is 24%. Further, formation of brown carbon is also increased in the presence of NOx. These results highlight the capacity of NOx to enhance SOA formation from phenolic compounds in biomass burning and open the door to further exploration.