Detailed characterization of organic carbon from fire: Capitalizing on analytical advances to improve atmospheric models

Biomass burning " including wildfires, agricultural burning and prescribed fires " injects large amounts of particulate matter (PM) and reactive trace gases to the atmosphere, affecting air quality and climate. Advances in analytical technology have allowed improvements in identification and quantification of non-methane volatile organic carbon (VOC) species in fire emissions. Application of new techniques including two-dimensional gas chromatography time-of-flight mass spectrometry (GCxGC/TOFMS) leads to unprecedented identification of total detected VOC mass and associated chemical properties. Hundreds of chemical species emitted from fires can now be identified and quantified. To preserve computational speed in chemical transport models, individual NMOCs are mapped to a smaller number of lumped surrogate species, typically grouped by reactivity with the hydroxyl radical (€ OH). Yet, underlying a priori assumptions regarding mapping individual compounds to simplified chemical mechanism surrogates may inhibit atmospheric models from capitalizing on recent measurement advances. Mapping protocols often do not consider semi-volatile and solubility properties, all of which impact the fate and transport of trace species through the atmosphere. This reduction in modeled chemical complexity contributes to substantial uncertainties in simulations of biomass burning derived O 3 and PM. In this chapter we explore how a multi-dimensional physicochemical property characterization of VOC species emitted by biomass burning fire emissions and their mapping to existing gas-phase chemical mechanisms will enable more holistic and accurate descriptions of organic compounds in atmospheric models.