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Journal articles on the topic 'Photochemical model'

Author: Grafiati

Published: 4 June 2021

Last updated: 5 February 2022

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1

Huang, Y., D. Pagé, D. D. M. Wayner, and P. Mulder. "Radical-induced degradation of a lignin model compound. Decomposition of 1-phenyl-2-phenoxyethanol." Canadian Journal of Chemistry 73, no. 11 (1995): 2079–85. http://dx.doi.org/10.1139/v95-256.

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Reaction of 1-phenyl-2-phenoxyethanol (1) with thermally or photochemically generated tert-butoxyl radicals leads, via the intermediate ketyl radical, to the formation of the corresponding ketone, α-phenoxyacetophenone (4), as the only product at low conversion under an inert atmosphere. An approximately twofold increase in the product yield is observed when the reactions are carried out under oxygen. Under the photochemical conditions it is shown that 4 is the primary product and that acetophenone and phenol are formed as a result of secondary photolysis of 4. These data suggest that the rate constant for fragmentation of the ketyl radical derived from 1 is on the order of 10 s−1 at 298 K and contradict a report in the literature that suggests a rate constant of >106 s−1. The relevance of this study to the photodegradation of lignin and consequent photoyellowing is discussed and a revised mechanism for the photoyellowing of pulp is proposed. Keywords: ketyl radical, photochemical degradation, thermal degradation, lignin.

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2

Ollivier, J. L., M. Dobrijévic, and J. P. Parisot. "New photochemical model of Saturn’s atmosphere." Planetary and Space Science 48, no. 7-8 (2000): 699–716. http://dx.doi.org/10.1016/s0032-0633(00)00035-0.

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3

Moses, Julianne I. "SL9 impact chemistry: Long-term photochemical evolution." International Astronomical Union Colloquium 156 (May 1996): 243–68. http://dx.doi.org/10.1017/s0252921100115532.

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One-dimensional photochemical models are used to provide an assessment of the chemical composition of the Shoemaker-Levy 9 impact sites soon after the impacts, and over time, as the impact-derived molecular species evolve due to photochemical processes. Photochemical model predictions are compared with the observed temporal variation of the impact-derived molecules in order to place constraints on the initial composition at the impact sites and on the amount of aerosol debris deposited in the stratosphere. The time variation of NH3, HCN, OCS, and H2S in the photochemical models roughly parallels that of the observations. S2persists too long in the photochemical models, suggesting that some of the estimated chemical rates constants and/or initial conditions(e.g., the assumed altitude distribution or abundance of S2) are incorrect. Models predict that CS and CO persist for months or years in the jovian stratosphere. Observations indicate that the model results with regard to CS are qualitatively correct (although the measured CS abundance demonstrates the need for a larger assumed initial abundance of CS in the models), but that CO appears to be more stable in the models than is indicated by observations. The reason for this discrepancy is unknown. We use model-data comparisons to learn more about the unique photochemical processes occurring after the impacts.

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4

Yamartino, R. J., J. S. Scire, G. R. Carmichael, and Y. S. Chang. "The CALGRID mesoscale photochemical grid model—I. Model formulation." Atmospheric Environment. Part A. General Topics 26, no. 8 (1992): 1493–512. http://dx.doi.org/10.1016/0960-1686(92)90134-7.

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5

Siampiringue, Marie, Rajae Chahboune, Pascal Wong-Wah-Chung, and Mohamed Sarakha. "Carbaryl Photochemical Degradation on Soil Model Surfaces." Soil Systems 3, no. 1 (2019): 17. http://dx.doi.org/10.3390/soilsystems3010017.

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The phototransformation of carbaryl was investigated upon solar light exposure on three surfaces, silica, kaolin and sand, as soil models. By excitation with a Suntest set up at the surface of the three solid supports, the degradation of carbaryl followed first-order kinetics with a rate constant of 0.10 h−1. By using the Kubelka Munk model, the quantum yield disappearance at the surface of kaolin was evaluated to 2.4 × 10−3. Such a value is roughly one order of magnitude higher than that obtained in aqueous solutions. The results indicated that the particle size and the specific surface area of the various models have significant effects. The photo-oxidative properties as well as the byproduct elucidation by liquid chromatography combined with diode arrays (LC-DAD) and liquid chromatography coupled mass spectrometry (LC-MS) analyses allowed us to propose the degradation mechanism pathways. The main products were 1-naphtol and 2-hydroxy-1,4-naphthoquinone, which arise from a photo-oxidation process together with products from photo-Fries, photo-ejection and methyl carbamate hydrolysis. The toxicity tests clearly showed a significant decrease of the toxicity in the early stages of the irradiation. This clearly shows that the generated products are less toxic than the parent compound.

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6

Eichenbaum, Joseph W., Ayca Cinaroglu, Kenneth D. Eichenbaum, and Kirsten C. Sadler. "A zebrafish retinal graded photochemical stress model." Journal of Pharmacological and Toxicological Methods 59, no. 3 (2009): 121–27. http://dx.doi.org/10.1016/j.vascn.2009.02.006.

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7

Giorgi, F., and W. L. Chameides. "The rainout parameterization in a photochemical model." Journal of Geophysical Research: Atmospheres 90, no. D5 (1985): 7872–80. http://dx.doi.org/10.1029/jd090id05p07872.

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8

Nair, Hari, Mark Allen, Ariel D. Anbar, Yuk L. Yung, and R. Todd Clancy. "A Photochemical Model of the Martian Atmosphere." Icarus 111, no. 1 (1994): 124–50. http://dx.doi.org/10.1006/icar.1994.1137.

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9

ZACHARY, D. S., A. HAURIE, and I. SIVERGINA. "A REDUCED-ORDER PHOTOCHEMICAL AIR QUALITY MODEL." Cybernetics and Systems 35, no. 7-8 (2004): 579–93. http://dx.doi.org/10.1080/01969720490499281.

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10

Rasmussen, C. E., R. W. Schunk, and V. B. Wickwar. "A photochemical equilibrium model for ionospheric conductivity." Journal of Geophysical Research 93, A9 (1988): 9831. http://dx.doi.org/10.1029/ja093ia09p09831.

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11

Ortega, S., M. R. Soler, M. Alarcón, and R. Arasa. "MNEQA, an emissions model for photochemical simulations." Atmospheric Environment 43, no. 24 (2009): 3670–81. http://dx.doi.org/10.1016/j.atmosenv.2009.04.046.

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12

Cheng, H. R., H. Guo, S. M. Saunders, et al. "Assessing photochemical ozone formation in the Pearl River Delta with a photochemical trajectory model." Atmospheric Environment 44, no. 34 (2010): 4199–208. http://dx.doi.org/10.1016/j.atmosenv.2010.07.019.

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13

Ивашкин, A. Ivashkin, Новиков, et al. "Calculation Model of Photochemical Reactor with a Pulse Xenon Lamp for Water Treatment." Safety in Technosphere 5, no. 4 (2016): 51–57. http://dx.doi.org/10.12737/23762.

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A calculation model of the photochemical reactor based on a pulse xenon lamp and intended for water treatment from microbiological or chemical pollutants has been developed and realized. The model includes several calculation modules, each one describes the basic physical processes ongoing in the photochemical reactor: current’s form calculation module, pollutant’s particles trajectories calculation module, pulse lamp’s radiating characteristics calculation module, module for photometric calculation, determining an energy radiation dose of pollutant particles. Calculation of lamp’s radiating characteristics is based on ideas of gas discharge physics and on a number of empirical dependences, for calculation of other parameters has been used the numerical simulation. Model verification has been carried out by comparison of calculated and experimental efficiencies for two types of photochemical reactors’ designs with use of the known pollutant. The developed calculation model allows perform multi-parameter optimization for designs and regime parameters of pulse photochemical reactors for the purpose of increase their energy efficiency, and level of water treatment from various chemical and biological pollutants.

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14

Lei, W., B. de Foy, M. Zavala, R. Volkamer, and L. T. Molina. "Characterizing ozone production in the Mexico City Metropolitan Area: a case study using a chemical transport model." Atmospheric Chemistry and Physics 7, no. 5 (2007): 1347–66. http://dx.doi.org/10.5194/acp-7-1347-2007.

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Abstract. An episodic simulation is conducted to characterize midday (12:00–17:00 CDT) ozone (O3) photochemical production and to investigate its sensitivity to emission changes of ozone precursors in the Mexico City Metropolitan Area (MCMA) during an "O3-South" meteorological episode using the Comprehensive Air Quality Model with extensions (CAMx). High Ox (O3+NO2) photochemical production rates of 10–80 ppb/h are predicted due to the high reactivity of volatile organic compounds (VOCs) in which alkanes, alkenes, and aromatics exert comparable contributions. The predicted ozone production efficiency is between 4–10 O3 molecules per NOx molecule oxidized, and increases with VOC-to-NO2 reactivity ratio. Process apportionment analyses indicate significant outflow of pollutants such as O3 and peroxyacetyl nitrate (PAN) from the urban area to the surrounding regional environment. PAN is not in chemical-thermal equilibrium during the photochemically active periods. Sensitivity studies of O3 production suggest that O3 formation in the MCMA urban region with less chemical aging (NOz/NOy<0.3) is VOC-limited. Both the simulated behavior of O3 production and its sensitivities to precursors suggest that midday O3 formation during this episode is VOC-sensitive in the urban region on the basis of the current emissions inventory estimates, and current NOx levels depress the O3 production.

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15

Lei, W., B. de Foy, M. Zavala, R. Volkamer, and L. T. Molina. "Characterizing ozone production in the Mexico City Metropolitan Area: a case study using a chemical transport model." Atmospheric Chemistry and Physics Discussions 6, no. 4 (2006): 7959–8009. http://dx.doi.org/10.5194/acpd-6-7959-2006.

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Abstract. An episodic simulation is conducted to characterize ozone (O3) photochemical production and investigate its sensitivity to emission changes of ozone precursors in the Mexico City Metropolitan Area (MCMA) using the Comprehensive Air Quality Model with extensions (CAMx). High Ox (O3+NO2) photochemical production rates of 10–80 ppb/h are predicted due to the high reactivity of volatile organic compounds (VOCs) in which alkanes, alkenes, and aromatics exert comparable contributions. The predicted ozone production efficiency is between 4–10 O3 molecules per NOx molecule oxidized, and increases with VOC-to-NO2 reactivity ratio. Process apportionment analyses indicate significant outflow of pollutants such as O3 and peroxyacetyl nitrate (PAN) from the urban area to the surrounding regional environment. PAN is not in chemical-thermal equilibrium during the photochemically active periods. Sensitivity studies of O3 production suggest that O3 formation in the MCMA urban region with less chemical aging (NOz/NOy<0.3) is VOC-limited. Both the simulated behavior of O3 production and its sensitivities to precursors suggest that midday O3 formation during this episode is VOC sensitive in the urban region on the basis of the current emissions inventory. More episodic studies are needed to construct a comprehensive and representative picture of the O3 production characteristics and its response to emission controls.

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16

Hess, G. D. "A photochemical model for air quality assessment: Model description and verification." Atmospheric Environment (1967) 23, no. 3 (1989): 643–60. http://dx.doi.org/10.1016/0004-6981(89)90013-9.

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17

Kawano, Ken-Ichi, Yasuhiko Ikeda, Kazunao Kondo, and Kazuo Umemura. "Increased cerebral infarction by cyclic flow reductions: studies in the guinea pig MCA thrombosis model." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 275, no. 5 (1998): R1578—R1583. http://dx.doi.org/10.1152/ajpregu.1998.275.5.r1578.

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We have developed a photochemical model of thrombotic middle cerebral artery (MCA) occlusion in the guinea pig for investigating factors contributing to the development of cerebral infarction. In this model, cyclic flow reductions (CFRs) after recanalization of the MCA are a common observation and might contribute to the development of cerebral infarction. Therefore, we sought to measure the time course of recanalization of the guinea pig MCA after the artery had been occluded by a thrombus. Thrombotic occlusion of the MCA was induced by photochemical reaction between intravenously administered rose bengal and transluminal green light for 10, 15, 20, or 30 min. After the thrombotic occlusion of MCA and subsequent spontaneous thrombolysis, blood flow in the MCA gradually recovered to preocclusion level but with frequent CFRs. The recovery of MCA blood flow or duration of CFRs was dependent on the duration of photochemical reaction (extent of endothelial injury); thus, for a 30-min photochemical reaction, CFRs were still observed 24 h after photochemical reaction. In separate experiments, we also investigated the effect of permanent occlusion of the MCA, which was induced by electrocoagulation in the vessel on cerebral infarction. The infarct volume in the permanent occlusion model was smaller than the maximum value in the thrombotic occlusion model (12.5 vs. 17.4%; P < 0.05, n = 6). CFRs may constitute an important factor contributing to the extent of cerebral infarction.

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18

Sadoqi, M., S. Kumar, and Y. Yamada. "Photochemical and Photothermal Model for Pulsed-Laser Ablation." Journal of Thermophysics and Heat Transfer 16, no. 2 (2002): 193–99. http://dx.doi.org/10.2514/2.6684.

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19

Shih, Jhih-Shyang, Armistead G. Russell, and Gregory J. McRae. "An optimization model for photochemical air pollution control." European Journal of Operational Research 106, no. 1 (1998): 1–14. http://dx.doi.org/10.1016/s0377-2217(97)00359-7.

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20

Krasnopolsky, Vladimir A. "Nighttime photochemical model and night airglow on Venus." Planetary and Space Science 85 (September 2013): 78–88. http://dx.doi.org/10.1016/j.pss.2013.05.022.

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21

Montecinos Geisse, S., and H. D. Doebner. "Dynamical systems based on a mesospheric photochemical model." Physics Letters A 241, no. 4-5 (1998): 269–73. http://dx.doi.org/10.1016/s0375-9601(98)00136-4.

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22

Gabusi, Veronica, and Marialuisa Volta. "A methodology for seasonal photochemical model simulation assessment." International Journal of Environment and Pollution 24, no. 1/2/3/4 (2005): 11. http://dx.doi.org/10.1504/ijep.2005.007381.

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23

Costen, Robert C., Geoffrey M. Tennille, and Joel S. Levine. "Cloud pumping in a one-dimensional photochemical model." Journal of Geophysical Research 93, no. D12 (1988): 15941. http://dx.doi.org/10.1029/jd093id12p15941.

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24

Krasnopolsky, Vladimir A. "A photochemical model of Titan's atmosphere and ionosphere." Icarus 201, no. 1 (2009): 226–56. http://dx.doi.org/10.1016/j.icarus.2008.12.038.

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25

Wakamatsu, Shinji, Toshimasa Ohara, and Itsushi Uno. "Springtime Photochemical Air Pollution in Osaka: Model Analysis." Journal of Applied Meteorology 37, no. 10 (1998): 1107–16. http://dx.doi.org/10.1175/1520-0450(1998)037<1107:spapio>2.0.co;2.

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26

Brown-McDonald, Jessie, Seth Berg, Marci Peralto, and Carmen Works. "Photochemical studies of iron-only hydrogenase model compounds." Inorganica Chimica Acta 362, no. 2 (2009): 318–24. http://dx.doi.org/10.1016/j.ica.2008.03.110.

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27

Krasnopolsky, Vladimir A. "A photochemical model of Pluto's atmosphere and ionosphere." Icarus 335 (January 2020): 113374. http://dx.doi.org/10.1016/j.icarus.2019.07.008.

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28

Carvalho, Thiago C., Thomas E. La Cruz, and Jose E. Tábora. "A photochemical kinetic model for solid dosage forms." European Journal of Pharmaceutics and Biopharmaceutics 120 (November 2017): 63–72. http://dx.doi.org/10.1016/j.ejpb.2017.08.010.

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29

de Groot, J. A., R. van der Steen, R. Fokkens, and J. Lugtenburg. "Synthesis and photochemical reactivity of bilirubin model compounds." Recueil des Travaux Chimiques des Pays-Bas 101, no. 1 (2010): 35–40. http://dx.doi.org/10.1002/recl.19821010103.

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30

Dorf, M., H. Bösch, A. Butz, et al. "Balloon-borne stratospheric BrO measurements: comparison with Envisat/SCIAMACHY BrO limb profiles." Atmospheric Chemistry and Physics Discussions 5, no. 6 (2005): 13011–52. http://dx.doi.org/10.5194/acpd-5-13011-2005.

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Abstract. For the first time, results of all four existing stratospheric BrO profiling instruments, are presented and compared with reference to the SLIMCAT 3-dimensional chemical transport model (3-D CTM). Model calculations are used to infer a BrO profile validation set, measured by 3 different balloon sensors, for the new Envisat/SCIAMACHY (ENVIronment SATellite/SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) satellite instrument. The balloon observations include (a) balloon-borne in situ resonance fluorescence detection of BrO, (b) balloon-borne solar occultation DOAS measurements (Differential Optical Absorption Spectroscopy) of BrO in the UV, and (c) BrO profiling from the solar occultation SAOZ (Systeme d'Analyse par Observation Zenithale) balloon instrument. Since stratospheric BrO is subject to considerable diurnal variation and none of the measurements are performed close enough in time and space for a direct comparison, all balloon observations are considered with reference to outputs from the 3-D CTM. The referencing is performed by forward and backward air mass trajectory calculations to match the balloon with the satellite observations. The diurnal variation of BrO is considered by 1-D photochemical model calculation along the trajectories. The 1-D photochemical model is initialised with output data of the 3-D model with additional constraints on the vertical transport, the total amount and photochemistry of stratospheric bromine as given by the various balloon observations. Total [Bry]=(20.1±2.8)pptv obtained from DOAS BrO observations at mid-latitudes in 2003, serves as an upper limit of the comparison. Most of the balloon observations agree with the photochemical model predictions within their given error estimates. First retrieval exercises of BrO limb profiling from the SCIAMACHY satellite instrument agree to <±50% with the photochemically-corrected balloon observations, and tend to show less agreement below 20 km.

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31

Huang, Weiwen, Qiuyue Zhao, Qian Liu, et al. "Assessment of atmospheric photochemical reactivity in the Yangtze River Delta using a photochemical box model." Atmospheric Research 245 (November 2020): 105088. http://dx.doi.org/10.1016/j.atmosres.2020.105088.

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32

Wang, X., Y. Zhang, Y. Hu, et al. "Process analysis and sensitivity study of regional ozone formation over the Pearl River Delta, China, during the PRIDE-PRD2004 campaign using the CMAQ model." Atmospheric Chemistry and Physics Discussions 9, no. 6 (2009): 26833–80. http://dx.doi.org/10.5194/acpd-9-26833-2009.

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Abstract. In this study, the Community Multiscale Air Quality (CMAQ) modeling system is used to simulate the ozone (O3) episodes during the Program of Regional Integrated Experiments of Air Quality over the Pearl River Delta, China, in October 2004 (PRIDE-PRD2004). The simulation suggests that O3 pollution is a regional phenomenon in the PRD. Elevated O3 levels often occurred in the southwestern inland PRD, Pearl River estuary (PRE), and southern coastal areas during the 1-month field campaign. Three evolution patterns of simulated surface O3 are summarized based on different near-ground flow conditions. More than 75% of days featured interaction between weak synoptic forcing and local sea-land circulations. Integrated process rate (IPR) analysis shows that photochemical production is the dominant contributor to O3 enhancement from 09:00 to 15:00 LST (local standard time) in the atmospheric boundary layer over most areas with elevated O3 occurrence in the mid-afternoon. The simulated ozone production efficiency is 2–8 O3 molecules per NOx molecule oxidized in areas with high O3 chemical production. Precursors of O3 originating from different source regions in the central PRD are mixed during transport to downwind rural areas during nighttime and early morning, where they then contribute to the daytime O3 photochemical production. Such close interactions among precursor emissions, transports, and O3 photochemical production result in the regional O3 pollution over the PRD. Sensitivity studies suggest that O3 formation is volatile organic compound-limited in the central inland PRD, PRE, and surrounding coastal areas with less chemical aging (NOx/NOy>0.6), but is NOx-limited in the rural southwestern PRD with photochemically aged air (NOx/NOy<0.3).

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33

van Norren, D. "Photochemical Damage to the Eye." Physiology 6, no. 5 (1991): 232–34. http://dx.doi.org/10.1152/physiologyonline.1991.6.5.232.

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From a simple model with two retinal photosensitizers, the shape of the threshold curve for light damage can be predicted. Because the action spectrum for light damage is also known, from this model the damage threshold can be calculated for an arbitrary light source.

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34

Derwent, Richard G., and Tim P. Murrells. "Are photochemical oxidant control strategies robust to the choice of chemical mechanism?" Environmental Chemistry 10, no. 3 (2013): 234. http://dx.doi.org/10.1071/en12150.

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Environmental context Throughout the world there are many places where ozone levels are elevated above internationally accepted guidelines set to protect human health. Policy makers use air quality models to formulate emission control strategies to achieve these air quality goals for ozone. There are large uncertainties in these air quality models that mask the sensitivity of the model control strategies to chemical mechanism choice. Abstract Monte Carlo sampling of pre-specified parameter ranges has been used to replace a single ‘best estimate’ photochemical trajectory model run with 11 694 ‘acceptable’ model runs that are each consistent with the observations of elevated O3 during the PUMA (Pollution in the Urban Midlands Atmosphere) campaign in the UK, West Midlands during 1999. These 11 694 ‘acceptable’ parameter sets were then used for probabilistic evaluation of photochemical oxidant control strategies, based on 30% reductions in volatile organic compounds and NOx precursor emissions and on precursor emission projections to 2020. The sensitivity of single ‘best estimate’ model runs to chemical mechanism choice gave some indication of the robustness of photochemical oxidant control strategies. However, Monte Carlo parametric uncertainty analysis showed that sensitivity to mechanism choice failed to indicate the magnitudes of the likely uncertainty ranges in the O3 responses to photochemical oxidant control strategies. Furthermore, Monte Carlo uncertainty analysis showed that there may be O3 air quality disbenefits from 30% NOx emission reduction that were not apparent from ‘best estimate’ runs.

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35

Saniabadi, Abby R., Kazuo Umemura, Nobuteru Matsumoto, Sadayuki Sakuma, and Mitsuyoshi Nakashima. "Vessel Wall Injury and Arterial Thrombosis Induced by a Photochemical Reaction." Thrombosis and Haemostasis 73, no. 05 (1995): 868–72. http://dx.doi.org/10.1055/s-0038-1653883.

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SummaryArterial thrombosis may be initiated in an experimental animal by a photochemical reaction between transmural green light and i.v. administered Rose Bengal, a photosensitizer dye. In this study, scanning electron microscopy has been used to reveal the nature of vessel injury and the cellular composition of the photochemically induced thrombus. A 5 mm segment of the guinea pig femoral artery was occluded by a thrombus about 10 min after irradiation with green light in the presence of systemically administered Rose Bengal. Electron microscopy revealed that following photochemical reaction, endothelial cells first contract and, with further irradiation, become detached from the vessel wall, with their cell membrane being destroyed at the irradiated site where an occlusive platelet-rich thrombus was formed. Endothelial cell injury and vessel occlusion could be completely inhibited by the aminothiol, DL-cysteine administered i.v. 1 min after Rose Bengal. The mechanism of endothelial injury in this model appears to be by singlet molecular oxygen, 1O2 formed by energy transfer from the photo-excited dye to O2.

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36

Su, Ming-Der. "A model study on the photochemical isomerization of isothiazoles and thiazoles." Phys. Chem. Chem. Phys. 16, no. 32 (2014): 17030–42. http://dx.doi.org/10.1039/c4cp01895h.

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37

Dorf, M., H. Bösch, A. Butz, et al. "Balloon-borne stratospheric BrO measurements: comparison with Envisat/SCIAMACHY BrO limb profiles." Atmospheric Chemistry and Physics 6, no. 9 (2006): 2483–501. http://dx.doi.org/10.5194/acp-6-2483-2006.

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Abstract. For the first time, results of four stratospheric BrO profiling instruments, are presented and compared with reference to the SLIMCAT 3-dimensional chemical transport model (3-D CTM). Model calculations are used to infer a BrO profile validation set, measured by 3 different balloon sensors, for the new Envisat/SCIAMACHY (ENVIronment SATellite/SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) satellite instrument. The balloon observations include (a) balloon-borne in situ resonance fluorescence detection of BrO (Triple), (b) balloon-borne solar occultation DOAS measurements (Differential Optical Absorption Spectroscopy) of BrO in the UV, and (c) BrO profiling from the solar occultation SAOZ (Systeme d'Analyse par Observation Zenithale) balloon instrument. Since stratospheric BrO is subject to considerable diurnal variation and none of the measurements are performed close enough in time and space for a direct comparison, all balloon observations are considered with reference to outputs from the 3-D CTM. The referencing is performed by forward and backward air mass trajectory calculations to match the balloon with the satellite observations. The diurnal variation of BrO is considered by 1-D photochemical model calculation along the trajectories. The 1-D photochemical model is initialised with output data of the 3-D model with additional constraints on the vertical transport, the total amount and photochemistry of stratospheric bromine as given by the various balloon observations. Total [Bry]=(20.1±2.5) pptv obtained from DOAS BrO observations at mid-latitudes in 2003, serves as an upper limit of the comparison. Most of the balloon observations agree with the photochemical model predictions within their given error estimates. First retrieval exercises of BrO limb profiling from the SCIAMACHY satellite instrument on average agree to around 20% with the photochemically-corrected balloon observations of the remote sensing instruments (SAOZ and DOAS). An exception is the in situ Triple profile, in which the balloon and satellite data mostly does not agree within the given errors. In general, the satellite measurements show systematically higher values below 25 km than the balloon data and a change in profile shape above about 25 km.

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38

He, Zhuoran, Xuemei Wang, Zhenhao Ling, et al. "Contributions of different anthropogenic volatile organic compound sources to ozone formation at a receptor site in the Pearl River Delta region and its policy implications." Atmospheric Chemistry and Physics 19, no. 13 (2019): 8801–16. http://dx.doi.org/10.5194/acp-19-8801-2019.

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Abstract. Volatile organic compounds (VOCs) are key precursors of photochemical smog. Quantitatively evaluating the contributions of VOC sources to ozone (O3) formation could provide valuable information for emissions control and photochemical pollution abatement. This study analyzed continuous measurements of VOCs during the photochemical season in 2014 at a receptor site (Heshan site, HS) in the Pearl River Delta (PRD) region, where photochemical pollution has been a long-standing issue. The averaged mixing ratio of measured VOCs was 34±3 ppbv, with the largest contribution from alkanes (17±2 ppbv, 49 %), followed by aromatics, alkenes and acetylene. The positive matrix factorization (PMF) model was applied to resolve the anthropogenic sources of VOCs, coupled with a photochemical-age-based parameterization that better considers the photochemical processing effects. Four anthropogenic emission sources were identified and quantified, with gasoline vehicular emission as the most significant contributor to the observed VOCs, followed by diesel vehicular emissions, biomass burning and solvent usage. The O3 photochemical formation regime at the HS was identified as VOC-limited by a photochemical box model with the master chemical mechanism (PBM-MCM). The PBM-MCM model results also suggested that vehicular emission was the most important source to the O3 formation, followed by biomass burning and solvent usage. Sensitivity analysis indicated that combined VOC and NOx emission controls would effectively reduce incremental O3 formation when the ratios of VOC-to-NOx emission reductions were > 3.8 for diesel vehicular emission, > 4.6 for solvent usage, > 4.6 for biomass burning and 3.3 for gasoline vehicular emission. Based on the above results, a brief review of the policies regarding the control of vehicular emissions and biomass burning in the PRD region from a regional perspective were also provided in this study. It reveals that different policies have been, and continue to be, implemented and formulated and could help to alleviate the photochemical pollution in the PRD region. Nevertheless, evaluation of the cost-benefit of each policy is still needed to improve air quality.

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Tvauri, Inga, Soslan Khubezhov, Bela Gergieva, et al. "Subnanometer Aluminium Oxide Film as a Model Photochemical Sensor." Key Engineering Materials 644 (May 2015): 153–56. http://dx.doi.org/10.4028/www.scientific.net/kem.644.153.

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The growth and the atomic structure of alumina films of submonolayer to multilayer thickness evaporated onto the surface of Mo (110) crystal have been studied by Auger electron spectroscopy, high resolution electron energy loss spectroscopy and scanning tunneling microscopy. It is shown that the stoichiometry of the submonolayer film corresponds to that of the bulk oxide, and after achieving two monolayers the properties of the film largely resemble the properties of massive alumina. Deposition of the oxide at a substrate temperature of 1100 K results in the film structure corresponding to α-Al2O3. Such ultrathin oxide film is of considerable potential application in sensor physics and technology.

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Melas, Dimitrios, Ioannis Kioutsioukis, and Ioannis C. Ziomas. "Neural Network Model for Predicting Peak Photochemical Pollutant Levels." Journal of the Air & Waste Management Association 50, no. 4 (2000): 495–501. http://dx.doi.org/10.1080/10473289.2000.10464039.

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Staffelbach, T., A. Neftel, and L. W. Horowitz. "Photochemical oxidant formation over southern Switzerland: 2. Model results." Journal of Geophysical Research: Atmospheres 102, no. D19 (1997): 23363–73. http://dx.doi.org/10.1029/97jd00932.

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Sakaguchi, Hidetsugu, Daishiro Kijima, Shunsuke Chatani, and Toshiaki Hattori. "Pattern Formation in a Simple Model of Photochemical Reaction." Journal of the Physical Society of Japan 80, no. 12 (2011): 124001. http://dx.doi.org/10.1143/jpsj.80.124001.

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Ellozy, Aziza R., Ren H. Wang, and James Dillon. "MODEL STUDIES ON THE PHOTOCHEMICAL PRODUCTION OF LENTICULAR FLUOROPHORES." Photochemistry and Photobiology 59, no. 4 (1994): 479–84. http://dx.doi.org/10.1111/j.1751-1097.1994.tb05068.x.

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Gorbunov, Maxim Y., Fedor I. Kuzminov, Victor V. Fadeev, John Dongun Kim, and Paul G. Falkowski. "A kinetic model of non-photochemical quenching in cyanobacteria." Biochimica et Biophysica Acta (BBA) - Bioenergetics 1807, no. 12 (2011): 1591–99. http://dx.doi.org/10.1016/j.bbabio.2011.08.009.

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Jin, Shengxin, and Kenneth Demerjian. "A photochemical box model for urban air quality study." Atmospheric Environment. Part B. Urban Atmosphere 27, no. 4 (1993): 371–87. http://dx.doi.org/10.1016/0957-1272(93)90015-x.

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Paalme, L., N. Irha, E. Urbas, A. Tsyban, and U. Kirso. "Model studies of photochemical oxidation of carcinogenic polyaromatic hydrocarbons." Marine Chemistry 30 (January 1990): 105–11. http://dx.doi.org/10.1016/0304-4203(90)90064-j.

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ZHU, X. Y. "ISOTOPE EFFECT IN SURFACE PHOTOCHEMICAL PROCESSES: EXPERIMENT AND THEORY." Modern Physics Letters B 06, no. 30 (1992): 1893–910. http://dx.doi.org/10.1142/s0217984992001605.

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A photochemical process in the adsorbate state has an inherent isotope or mass effect. This is because the presence of a solid surface introduces efficient relaxation channels for the electronically excited molecule. Competition between the chemical event and the quenching process is mass-dependent. Depending on the details of the dynamic energy transfer process, the isotope effect in a surface photochemical event can depend on either the mass or the internal reduced mass of the desorbing/dissociating particle. Measurements of isotope effect in UV surface photochemistry have provided insight into two mechanistic models, i.e., the classic Menzel-Gomer-Redhead (MGR) model and its recent variation, the vibration-mediated UV photodesorption (VMPD) model.

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Porcar-Castell, Albert, Jaana Bäck, Eija Juurola, and Pertti Hari. "Dynamics of the energy flow through photosystem II under changing light conditions: a model approach." Functional Plant Biology 33, no. 3 (2006): 229. http://dx.doi.org/10.1071/fp05133.

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Several biochemical models of photosynthesis exist that consider the effects of the dynamic adjustment of enzymatic and stomatal processes on carbon assimilation under fluctuating light. However, the rate of electron transport through the light reactions is commonly modelled by means of an empirical equation, parameterised with data obtained at the steady state. A steady-state approach cannot capture the dynamic nature of the adjustment of the light reactions under fluctuating light. Here we present a dynamic model approach for photosystem II that considers the adjustments in the regulative non-photochemical processes. The model is initially derived to account for changes occurring at the seconds-to-minutes time-scale under field conditions, and is parameterised and tested with chlorophyll fluorescence data. Results derived from this model show good agreement with experimentally obtained photochemical and non-photochemical quantum yields, providing evidence for the effect that the dark reactions exert in the adjustment of the energy flows at the light reactions. Finally, we compare the traditional steady-state approach with our dynamic approach and find that the steady-state approach produces an underestimation of the modelled electron transport rate (ETR) under rapidly fluctuating light (1 s or less), whereas it produces overestimations under slower fluctuations of light (5 s or more).

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Ma, Prettiny K., Yunliang Zhao, Allen L. Robinson, et al. "Evaluating the impact of new observational constraints on P-S/IVOC emissions, multi-generation oxidation, and chamber wall losses on SOA modeling for Los Angeles, CA." Atmospheric Chemistry and Physics 17, no. 15 (2017): 9237–59. http://dx.doi.org/10.5194/acp-17-9237-2017.

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Abstract. Secondary organic aerosol (SOA) is an important contributor to fine particulate matter (PM) mass in polluted regions, and its modeling remains poorly constrained. A box model is developed that uses recently published literature parameterizations and data sets to better constrain and evaluate the formation pathways and precursors of urban SOA during the CalNex 2010 campaign in Los Angeles. When using the measurements of intermediate-volatility organic compounds (IVOCs) reported in Zhao et al. (2014) and of semi-volatile organic compounds (SVOCs) reported in Worton et al. (2014) the model is biased high at longer photochemical ages, whereas at shorter photochemical ages it is biased low, if the yields for VOC oxidation are not updated. The parameterizations using an updated version of the yields, which takes into account the effect of gas-phase wall losses in environmental chambers, show model–measurement agreement at longer photochemical ages, even though some low bias at short photochemical ages still remains. Furthermore, the fossil and non-fossil carbon split of urban SOA simulated by the model is consistent with measurements at the Pasadena ground site. Multi-generation oxidation mechanisms are often employed in SOA models to increase the SOA yields derived from environmental chamber experiments in order to obtain better model–measurement agreement. However, there are many uncertainties associated with these aging mechanisms. Thus, SOA formation in the model is compared to data from an oxidation flow reactor (OFR) in order to constrain SOA formation at longer photochemical ages than observed in urban air. The model predicts similar SOA mass at short to moderate photochemical ages when the aging mechanisms or the updated version of the yields for VOC oxidation are implemented. The latter case has SOA formation rates that are more consistent with observations from the OFR though. Aging mechanisms may still play an important role in SOA chemistry, but the additional mass formed by functionalization reactions during aging would need to be offset by gas-phase fragmentation of SVOCs. All the model cases evaluated in this work show a large majority of the urban SOA (70–83 %) at Pasadena coming from the oxidation of primary SVOCs (P-SVOCs) and primary IVOCs (P-IVOCs). The importance of these two types of precursors is further supported by analyzing the percentage of SOA formed at long photochemical ages (1.5 days) as a function of the precursor rate constant. The P-SVOCs and P-IVOCs have rate constants that are similar to highly reactive VOCs that have been previously found to strongly correlate with SOA formation potential measured by the OFR. Finally, the volatility distribution of the total organic mass (gas and particle phase) in the model is compared against measurements. The total SVOC mass simulated is similar to the measurements, but there are important differences in the measured and modeled volatility distributions. A likely reason for the difference is the lack of particle-phase reactions in the model that can oligomerize and/or continue to oxidize organic compounds even after they partition to the particle phase.

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Seylar, Joshua, Dmytro Stasiouk, Davide L. Simone, Vikas Varshney, James E. Heckler та Ruel McKenzie. "Breaking the bottleneck: stilbene as a model compound for optimizing 6π e− photocyclization efficiency". RSC Advances 11, № 12 (2021): 6504–8. http://dx.doi.org/10.1039/d0ra10619d.

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