Assessment of SAPRC07 with updated isoprene chemistry against outdoor chamber experiments

作者：Chen Yuzhi; Sexton Kenneth G; Jerry Roger E; Surratt Jason D; Vizuete William^*

来源：Atmospheric Environment, 2015, 105: 109-120.

DOI：10.1016/j.atmosenv.2015.01.042

• Atmospheric chemical mechanism
• Isoprene
• Smog chamber
• SAPRC07

Isoprene, the most emitted non-methane hydrocarbon, is known to influence ozone (O-3) formation in urban areas rich with biogenic emissions. To keep up with the recent advance on isoprene oxidation chemistry including the identification of isoprene epoxydiols (IEPOX) as a precursor to secondary organic aerosol (SOA), Xie et al. (2013) updated the SAPRC (Statewide Air Pollution Research Center)-07 chemical mechanism. It is currently unknown how the Xie modification of SAPRC07 impacts the ability of the model to predict O-3. In this study we will evaluate the Xie mechanism with simulations of 24 isoprene experiments from the UNC Dual Gas-phase Chamber. Our results suggest that the new mechanism increases NOx (nitrogen oxides) inter-conversion and produces more O-3 than SAPRC07 for all experiments. In lower-NOx experiments, the new mechanism worsens O-3 performance in the wrong direction, increasing bias from 4.92% to 9.44%. We found increased NOx recycling from PANs accounts for that. This could be explained by more PANs made due to increased first generation volatile organic compound (VOC) products and hydroxyl radical (OH) production.

• 出版日期2015-3