Using GECKO-A to derive mechanistic understanding of secondary organic aerosol formation from the ubiquitous but understudied camphene

Abstract. Camphene, a dominant monoterpene emitted from both biogenic and pyrogenic sources, has been significantly understudied, particularly in regard to secondary organic aerosol (SOA) formation. When camphene represents significant fraction of emissions, the lack model parameterizations for can result inadequate representation gas-phase chemistry underprediction SOA In this work, first mechanistic study formation was performed using Generator Explicit Chemistry Kinetics Organics Atmosphere (GECKO-A). GECKO-A used generate chemical mechanisms two well-studied monoterpenes, α-pinene limonene, as well predict mass composition based on gas/particle partitioning theory. The simulations represented observed trends published reaction pathways yields under chamber-relevant photooxidation dark ozonolysis conditions. For conditions, 70 % simulated oxidation products remained gas phase compared 50 supporting predictions observations limonene having higher than equivalent top 10 particle-phase 37 %–50 formed 6 %–27 hydrocarbon reacted. To facilitate comparison with were run idealized atmospheric wherein oxidant levels controlled, peroxy radicals reacted equally HO2 NO. Metrics included reactivity profiles, time-evolution yields, physicochemical property distributions gas- products. controlled-reactivity demonstrated that (1) early stages oxidation, is predicted form very low-volatility products, lower which condense at low loadings; (2) final yield (46 %) relatively high, between (25 (74 %). A + mixture then surrogate represent camphene; while represented, volatility distribution not. demonstrate potential importance including parameterized by air quality models, three wildland fire fuels measured limonene. Using 50/50 increased 43 black spruce 56 %–108 Douglas fir. This detailed modeling subsequent highlights opportunities future measurement–model comparisons lays foundation developing are suitable modeling.