TY - JOUR
T1 - Simulating the Weekly Cycle of NOx-VOC-HOx-O3 Photochemical System in the South Coast of California During CalNex-2010 Campaign
AU - Cai, Chenxia
AU - Avise, Jeremy
AU - Kaduwela, Ajith
AU - DaMassa, John
AU - Warneke, Carsten
AU - Gilman, Jessica B.
AU - Kuster, William
AU - de Gouw, Joost
AU - Volkamer, Rainer
AU - Stevens, Philip
AU - Lefer, Barry
AU - Holloway, John S.
AU - Pollack, Ilana B.
AU - Ryerson, Thomas
AU - Atlas, Elliot
AU - Blake, Donald
AU - Rappenglueck, Bernhard
AU - Brown, Steven S.
AU - Dube, William P.
N1 - Funding Information:
The CalNex 2010 field study was jointly sponsored and conducted by the National Oceanic and Atmospheric Administration and the California Air Resources Board. CalNex field campaign data used in the work were downloaded from https://www.esrl.noaa.gov/csd/groups/csd7/measurements/2010calex. Routine ground measurement data are available at https://www.arb.ca.gov/adam/index.html. We thank all the CalNex participants for their support and contributions. Zhan Zhao at CARB provided us with the WRF model output used in this study, while Leonardo Ramirez and Maybelline Disuanco at CARB provided us with the emission inventories. We also thank James Kelly at United States EPA; Sang-Mi Lee at South Coast Air Quality Management District; and Eileen McCauley, Leon Dolislager, and Dazhong Yin at CARB for valuable input and discussion.
PY - 2019/3/27
Y1 - 2019/3/27
N2 - United States Environmental Protection Agency guidance on the use of photochemical models for assessing the efficacy of an emissions control strategy for ozone requires that modeling be used in a relative sense. Consequently, testing a modeling system's ability to predict changes in ozone resulting from emission changes is critical. We evaluate model simulations for precursor species (NOx, CO, and volatile organic compounds [VOCs]), radicals (OH and HO2), a secondary pollutant (O3), and the model response of these compounds to weekend/weekday emission changes during California Nexus study in 2010. The modeling system correctly simulated the broad spatial and temporal variation of NOx and O3 in California South Coast. Although the model generally underpredicted the daytime mixing ratios of NO2 at the surface and overpredicted the NO2 column, the simulated weekend to weekday ratios are consistent with each other and match the observed ratios well. The modeling system exhibited reasonable performance in simulating the VOC compounds with fossil fuel origins but has larger bias in simulating certain species associated with noncombustion sources. The modeling system successfully captured the weekend changes of the enhancement ratios for various VOC species to CO and the relative changes of HOx, which are indicators of faster chemical processing on weekends. This work demonstrates satisfactory model performances for O3 and most relevant chemical compounds with more robust performance in simulating weekend versus weekday changes. Improved planetary boundary layer height simulations, a better understanding of OH-HO2 cycling, continued improvement of emissions, especially urban biogenic emissions and emissions of oxygenated VOCs, are important for future model improvement.
AB - United States Environmental Protection Agency guidance on the use of photochemical models for assessing the efficacy of an emissions control strategy for ozone requires that modeling be used in a relative sense. Consequently, testing a modeling system's ability to predict changes in ozone resulting from emission changes is critical. We evaluate model simulations for precursor species (NOx, CO, and volatile organic compounds [VOCs]), radicals (OH and HO2), a secondary pollutant (O3), and the model response of these compounds to weekend/weekday emission changes during California Nexus study in 2010. The modeling system correctly simulated the broad spatial and temporal variation of NOx and O3 in California South Coast. Although the model generally underpredicted the daytime mixing ratios of NO2 at the surface and overpredicted the NO2 column, the simulated weekend to weekday ratios are consistent with each other and match the observed ratios well. The modeling system exhibited reasonable performance in simulating the VOC compounds with fossil fuel origins but has larger bias in simulating certain species associated with noncombustion sources. The modeling system successfully captured the weekend changes of the enhancement ratios for various VOC species to CO and the relative changes of HOx, which are indicators of faster chemical processing on weekends. This work demonstrates satisfactory model performances for O3 and most relevant chemical compounds with more robust performance in simulating weekend versus weekday changes. Improved planetary boundary layer height simulations, a better understanding of OH-HO2 cycling, continued improvement of emissions, especially urban biogenic emissions and emissions of oxygenated VOCs, are important for future model improvement.
KW - Nitrogen oxide
KW - Ozone
KW - South Coast Air Basin
KW - Volatile organic compounds
KW - Weekend effect
KW - hydroxyl and hydroperoxy radicals
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U2 - 10.1029/2018JD029859
DO - 10.1029/2018JD029859
M3 - Article
AN - SCOPUS:85064499714
VL - 124
SP - 3532
EP - 3555
JO - Journal of Geophysical Research: Atmospheres
JF - Journal of Geophysical Research: Atmospheres
SN - 2169-897X
IS - 6
ER -