Sensitivity analysis of the dependence of the Carbon Bond Mechanism IV (CBM-IV) on the initial air composition under an urban condition

2019 ◽  
Vol 215 ◽  
pp. 116860 ◽  
Author(s):  
Le Cao ◽  
Mengmeng Gao ◽  
Simeng Li ◽  
Ziwei Yi ◽  
Xianhong Meng
Keyword(s):  
Sensitivity Analysis ◽  
Carbon Bond ◽  
Urban Condition ◽  
Bond Mechanism

scholarly journals Simplification of Carbon Bond Mechanism IV (CBM-IV) under Different Initial Conditions by Using Concentration Sensitivity Analysis

Molecules ◽  
2019 ◽  
Vol 24 (13) ◽  
pp. 2463 ◽  
Author(s):  
Le Cao ◽  
Simeng Li ◽  
Ziwei Yi ◽  
Mengmeng Gao
Keyword(s):  
Sensitivity Analysis ◽  
Reaction Mechanism ◽  
Initial Conditions ◽  
Model Simulation ◽  
Computing Time ◽  
Reaction System ◽  
Carbon Bond ◽  
Reduced Mechanism ◽  
Concentration Sensitivity ◽  
Bond Mechanism

Carbon Bond Mechanism IV (CBM-IV) is a widely used reaction mechanism in which VOCs are grouped according to the molecular structure. In the present study, we applied a sensitivity analysis on the CBM-IV mechanism to clarify the importance of each reaction under two different initial conditions (urban and low-NO scenarios). The reactions that exert minor influence on the reaction system are then screened out from the mechanism, so that a reduced version of the CBM-IV mechanism under specific initial conditions can be obtained. We found that in a typical urban condition, 11 reactions can be removed from the original CBM-IV mechanism, and the deviation is less than 5% between the results using the original CBM-IV mechanism and the reduced mechanism. Moreover, in a low-NO initial condition, two more reactions, both of which are nitrogen-associated reactions, can be screened out from the reaction mechanism, while the accuracy of the simulation is still maintained. It is estimated that the reduction of the CBM-IV mechanism can save 11–14% of the computing time in the calculation of the chemistry in a box model simulation.

scholarly journals Study of Different Carbon Bond 6 (CB6) Mechanisms by Using a Concentration Sensitivity Analysis

2021 ◽  
Author(s):  
Le Cao ◽  
Simeng Li ◽  
Luhang Sun
Keyword(s):  
Air Pollution ◽  
Sensitivity Analysis ◽  
Nitrogen Oxides ◽  
The Other ◽  
Box Model ◽  
Carbon Bond ◽  
Surface Emission ◽  
Urban Condition ◽  
Concentration Sensitivity ◽  
Simulation Results

Abstract. Since the year 2010, different versions of the Carbon Bond 6 (CB6) mechanism have been developed, to accurately estimate the contribution to the air pollution by the chemistry. However, the discrepancies in simulation results brought about by the modifications between different versions of the CB6 mechanism are still not fully understood. Therefore, in the present study, we investigated the behavior of three different CB6 mechanisms (CB6r1, CB6r2 and CB6r3) in simulating ozone (O3), nitrogen oxides (NOx) and formaldehyde (HCHO) under an urban condition, by applying a concentration sensitivity analysis in a box model. The results show that when the surface emission is excluded, the O3 level predicted by CB6r1 is approximately 6 % and 8 % higher than that predicted by CB6r2 and CB6r3, specifically due to the change in the sink of CXO3 in the mechanism. In contrast, the levels of NOx and HCHO estimated by these three CB6 mechanisms are mostly similar, when the surface emission is turned off. After adding the surface emission, the simulated profiles of O3, NOx and HCHO obtained by CB6r2 and CB6r3 are similar. However, the deviation between the O3 levels provided by CB6r1 and the other two CB6 mechanisms (i.e. CB6r2 and CB6r3) is enlarged, because of the weakening of the ozone dependence on the emission of isoprene in CB6r1. Moreover, HCHO predicted by CB6r1 is found larger than that predicted by CB6r2 and CB6r3, which is caused by an enhanced dependence of HCHO on the emission of isoprene in CB6r1. Regarding to NOx, it was found that CB6r1 gives a higher value during the daytime and a lower value during the nighttime than the other two mechanisms, which is caused by the relatively stronger connection between the NOx prediction and the local chemistry in CB6r1, so that more NOx is consumed and converted to PANX (peroxyacyl nitrate with three and higher carbons) in the nighttime and more NOx is reformed by the photolysis of PANX in the daytime.

scholarly journals A Unique Barium−Carbon Bond:  Mechanism of Formation and Crystallographic Characterization

1998 ◽  
Vol 120 (27) ◽  
pp. 6722-6725 ◽  
Author(s):  
Matthias Westerhausen ◽  
Matthias H. Digeser ◽  
Heinrich Nöth ◽  
Thomas Seifert ◽  
Arno Pfitzner
Keyword(s):  
Mechanism Of Formation ◽  
Carbon Bond ◽  
Bond Mechanism

Study of different Carbon Bond 6 (CB6) mechanisms by using a concentration sensitivity analysis

2021 ◽  
Vol 21 (16) ◽  
pp. 12687-12714
Author(s):  
Le Cao ◽  
Simeng Li ◽  
Luhang Sun
Keyword(s):  
Sensitivity Analysis ◽  
Early Stage ◽  
Reaction System ◽  
The Other ◽  
Peroxy Radicals ◽  
Nox Formation ◽  
Carbon Bond ◽  
Surface Emission ◽  
Concentration Sensitivity ◽  
The Difference

Abstract. Since the year 2010, different versions of the Carbon Bond 6 (CB6) mechanism have been developed to accurately estimate the contribution to air pollution by the chemistry. In order to better understand the differences in simulation results brought about by the modifications between different versions of the CB6 mechanism, in the present study, we investigated the behavior of three different CB6 mechanisms (CB6r1, CB6r2 and CB6r3) in simulating ozone (O3), nitrogen oxides (NOx) and formaldehyde (HCHO) under two different emission conditions by applying a concentration sensitivity analysis in a box model. The results show that when the surface emission is weak, the O3 level predicted by CB6r1 is approximately 7 ppb higher than that predicted by CB6r2 and CB6r3, specifically due to the change in the sink of acyl peroxy radicals with high-order carbons (i.e., species CXO3) in the mechanism and the difference in the ozone dependence on the isoprene emission. In contrast, although CB6r1 estimates higher values of NOx and HCHO than the other two mechanisms at an early stage of the simulation, the levels of NOx and HCHO estimated by these three CB6 mechanisms at the end of the 7 d simulation are mostly similar, when the surface emission is weak. After the increase in the surface emission, the simulated profiles of O3, NOx and HCHO obtained by CB6r2 and CB6r3 were found to be nearly the same during the simulation period, but CB6r1 tends to estimate substantially higher values than CB6r2 and CB6r3. The deviation between the O3 levels provided by CB6r1 and the other two CB6 mechanisms (i.e., CB6r2 and CB6r3) was found to be enlarged compared with the weak-emission scenario because of the weaker dependence of ozone on the emission of isoprene in CB6r1 than those in CB6r2 and CB6r3 in this scenario. Moreover, HCHO predicted by CB6r1 was found to be larger than those predicted by CB6r2 and CB6r3, which is caused by an enhanced dependence of HCHO on the emission of isoprene in CB6r1. Regarding NOx, it was found that CB6r1 gives a higher value than the other two mechanisms, which is caused by the relatively stronger connection between the NOx prediction and the release of NO and NO2 in CB6r1 due to the change in the product of the reaction between isoprene and NO3 in CB6r1. Consequently, more emitted NOx is involved in the reaction system denoted by CB6r1, which enables a following NOx formation and thus a higher NOx prediction of CB6r1.

scholarly journals Impact of inert organic nitrate formation on ground-level ozone in a regional air quality model using the Carbon Bond Mechanism 4

1997 ◽  
Vol 24 (24) ◽  
pp. 3205-3208 ◽  
Author(s):  
P. Kasibhatla ◽  
W. L. Chameides ◽  
B. Duncan ◽  
M. Houyoux ◽  
C. Jang ◽  
...  
Keyword(s):  
Air Quality ◽  
Ground Level ◽  
Organic Nitrate ◽  
Air Quality Model ◽  
Quality Model ◽  
Carbon Bond ◽  
Ground Level Ozone ◽  
Regional Air Quality ◽  
Bond Mechanism

scholarly journals Sensitivity of Ozone Concentrations to Initial Concentrations Applying the Carbon Bond Mechanism IV

2003 ◽  
Vol 12 (11) ◽  
pp. 1159-1165
Author(s):  
Hwa-Woon Lee ◽  
Heon-Sook Kim ◽  
Eun-Joo Oh ◽  
Yeon-Hee Kim
Keyword(s):  
Carbon Bond ◽  
Ozone Concentrations ◽  
Bond Mechanism

The carbon-bond mechanism: a condensed kinetic mechanism for photochemical smog

1980 ◽  
Vol 14 (6) ◽  
pp. 690-700 ◽  
Author(s):  
Gary Z. Whitten ◽  
Henry. Hogo ◽  
James P. Killus
Keyword(s):  
Kinetic Mechanism ◽  
Photochemical Smog ◽  
Carbon Bond ◽  
Bond Mechanism

Impact of an Updated Carbon Bond Mechanism on Predictions from the CMAQ Modeling System: Preliminary Assessment

2008 ◽  
Vol 47 (1) ◽  
pp. 3-14 ◽  
Author(s):  
Golam Sarwar ◽  
Deborah Luecken ◽  
Greg Yarwood ◽  
Gary Z. Whitten ◽  
William P. L. Carter
Keyword(s):  
Hydrogen Peroxide ◽  
Organic Carbon ◽  
High Altitude ◽  
Rural Areas ◽  
Urban Areas ◽  
Model Performance ◽  
Preliminary Assessment ◽  
Carbon Bond ◽  
Carbon Concentrations ◽  
Bond Mechanism

Abstract An updated and expanded version of the Carbon Bond mechanism (CB05) has been incorporated into the Community Multiscale Air Quality (CMAQ) modeling system to more accurately simulate wintertime, pristine, and high-altitude situations. The CB05 mechanism has nearly 2 times the number of reactions relative to the previous version of the Carbon Bond mechanism (CB-IV). While the expansions do provide more detailed treatment of urban areas, most of the new reactions involve biogenics, toxics, and species potentially important to particulate formation and acid deposition. Model simulations were performed using the CB05 and the CB-IV mechanisms for the winter and summer of 2001. For winter with the CB05 mechanism, ozone, aerosol nitrate, and aerosol sulfate concentrations were within 1% of the results obtained with the CB-IV mechanism. Organic carbon concentrations were within 2% of the results obtained with the CB-IV mechanism. However, formaldehyde and hydrogen peroxide concentrations were lower by 25% and 32%, respectively, during winter with the CB05 mechanism. For the summer, ozone concentrations increased by 8% with the CB05 mechanism relative to the CB-IV mechanism. The aerosol sulfate, aerosol nitrate, and organic carbon concentrations with the CB05 mechanism decreased by 8%, 2%, and 10%, respectively. The formaldehyde and hydrogen peroxide concentrations with the CB05 mechanism were lower by 12% and 47%, respectively, during summer. Model performance with the CB05 mechanism improved at high-altitude conditions and in rural areas for ozone. Model performance also improved for organic carbon with the CB05 mechanism.

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