Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Assessment of SAPRC07 with updated isoprene chemistry against outdoor chamber experiments
https://orcid.org/0000-0002-2547-8428
Abstract Isoprene, the most emitted non-methane hydrocarbon, is known to influence ozone (O3) 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 O3. 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 O3 than SAPRC07 for all experiments. In lower-NOx experiments, the new mechanism worsens O3 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.
Highlights We evaluated the updated CMAQ version of SAPRC07 against chamber experiments. The mechanism shortens NO to NO2 conversion time and increases O3 production. In lower-NOX conditions the mechanism increases the bias of O3 from 4.9% to 9.4%. New Chemistry increases the reaction rate of VOCs and enhances radical production.
Assessment of SAPRC07 with updated isoprene chemistry against outdoor chamber experiments
https://orcid.org/0000-0002-2547-8428
Abstract Isoprene, the most emitted non-methane hydrocarbon, is known to influence ozone (O3) 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 O3. 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 O3 than SAPRC07 for all experiments. In lower-NOx experiments, the new mechanism worsens O3 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.
Highlights We evaluated the updated CMAQ version of SAPRC07 against chamber experiments. The mechanism shortens NO to NO2 conversion time and increases O3 production. In lower-NOX conditions the mechanism increases the bias of O3 from 4.9% to 9.4%. New Chemistry increases the reaction rate of VOCs and enhances radical production.
Assessment of SAPRC07 with updated isoprene chemistry against outdoor chamber experiments
https://orcid.org/0000-0002-2547-8428
Abstract Isoprene, the most emitted non-methane hydrocarbon, is known to influence ozone (O3) 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 O3. 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 O3 than SAPRC07 for all experiments. In lower-NOx experiments, the new mechanism worsens O3 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.
Highlights We evaluated the updated CMAQ version of SAPRC07 against chamber experiments. The mechanism shortens NO to NO2 conversion time and increases O3 production. In lower-NOX conditions the mechanism increases the bias of O3 from 4.9% to 9.4%. New Chemistry increases the reaction rate of VOCs and enhances radical production.
Assessment of SAPRC07 with updated isoprene chemistry against outdoor chamber experiments
Chen, Yuzhi (Autor:in) / Sexton, Kenneth G. (Autor:in) / Jerry, Roger E. (Autor:in) / Surratt, Jason D. (Autor:in) / Vizuete, William (Autor:in)
Atmospheric Environment ; 105 ; 109-120
20.01.2015
12 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch