ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-9-7461-2009 Detailed heterogeneous chemistry in an urban plume box model: reversible co-adsorption of O<sub>3</sub>, NO<sub>2</sub>, and H<sub>2</sub>O on soot coated with benzo[a]pyrene Springmann M. 1 Knopf D. A. 2 Riemer N. 3 Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA School of Marine and Atmospheric Sciences, Institute for Terrestrial and Planetary Atmospheres, Stony Brook University, Stony Brook, NY, USA Department of Atmospheric Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA 07 10 2009 9 19 7461 7479 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/9/7461/2009/acp-9-7461-2009.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/9/7461/2009/acp-9-7461-2009.pdf

This study assesses in detail the effects of heterogeneous chemistry on the particle surface and gas-phase composition by modeling the reversible co-adsorption of O<sub>3</sub>, NO<sub>2</sub>, and H<sub>2</sub>O on soot coated with benzo[a]pyrene (BaP) for an urban plume scenario over a period of five days. By coupling the Pöschl-Rudich-Ammann (PRA) kinetic framework for aerosols (Pöschl et al., 2007) to a box model version of the gas phase mechanism RADM2, we are able to track individual concentrations of gas-phase and surface species over the course of several days. The flux-based PRA formulation takes into account changes in the uptake kinetics due to changes in the chemical gas-phase and particle surface compositions. This dynamic uptake coefficient approach is employed for the first time in a broader atmospheric context of an urban plume scenario. Our model scenarios include one to three adsorbents and three to five coupled surface reactions. The results show a variation of the O<sub>3</sub> and NO<sub>2</sub> uptake coefficients of more than five orders of magnitude over the course of the simulation time and a decrease in the uptake coefficients in the various scenarios by more than three orders of magnitude within the first six hours. Thereafter, periodic peaks of the uptake coefficients follow the diurnal cycle of gas-phase O<sub>3</sub>-NO<sub>x</sub> reactions. Physisorption of water vapor reduces the half-life of the coating substance BaP by up to a factor of seven by permanently occupying ~75% of the soot surface. Soot emissions modeled by replenishing reactive surface sites lead to maximum gas-phase O<sub>3</sub> depletions of 41 ppbv and 7.8 ppbv for an hourly and six-hourly replenishment cycle, respectively. This conceptual study highlights the interdependence of co-adsorbing species and their non-linear gas-phase feedback. It yields further insight into the atmospheric importance of the chemical oxidation of particles and emphasizes the necessity to implement detailed heterogeneous kinetics in future modeling studies.

 References Aklilu, Y A. and Michelangeli, D V.: Box model investigation of the effect of soot particles on ozone downwind from an urban area through heterogeneous reactions, Environ. Sci. Technol., 38, 5540–5547, doi:10.1021/es035079x, 2004. Ammann, M. and Pöschl, U.: Kinetic model framework for aerosol and cloud surface chemistry and gas-particle interactions - Part~2: Exemplary practical applications and numerical simulations, Atmos. Chem. Phys., 7, 6025–6045, 2007. Ammann, M., Rössler, E., Baltensperger, U., and Kalberer, M.: Heterogeneous reaction of NO<sub>2</sub> on bulk soot samples, Laboratory of Radio- and Environmental Chemistry Annual Report 1997, Paul Scherrer Institute, Switzerland, 24, 1997. Ammann, M., Kalberer, M., Jost, D., Tobler, L., Rössler, E., Piguet, D., Gaggeler, H., and Baltensperger, U.: Heterogeneous production of nitrous acid on soot in polluted air masses, Nature, 395, 157–160, 1998. Arens, F., Gutzwiller, L., Baltensperger, U., Gaggeler, H., and Ammann, M.: Heterogeneous reaction of NO<sub>2</sub> on diesel soot particles, Environ. Sci. Technol., 35, 2191–2199, 2001. Arens, F., Gutzwiller, L., Gaggeler, H W., and Ammann, M.: The reaction of NO<sub>2</sub> with solid anthrarobin (1,2,10-trihydroxy-anthracene), Phys. Chem. Chem. Phys., 4, 3684–3690, doi:10.1039/b201713j, 2002. Atkinson, R., Baulch, D L., Cox, R A., Crowley, J N., Hampson Jr., R F., Kerr, J A., Rossi, M J., and Troe, J.: Summary of Evaluated Kinetic and Photochemical Data for Atmospheric Chemistry, Web Version, www.iupac-kinetic.ch.cam.ac.uk, last access: 27~March~2009, University of Cambridge, UK, 2001. Aubin, D G. and Abbatt, J P D.: Interaction of NO<sub>2</sub> with hydrocarbon soot: Focus on HONO yield, surface modification, and mechanism, J. Phys. Chem. A, 111, 6263–6273, doi:10.1021/jp068884h, 2007. Bernstein, J A., Alexis, N., Barnes, C., Bernstein, I L., Bernstein, J A., Nel, A., Peden, D., Diaz-Sanchez, D., Tarlo, S M., and Williams, P B.: Health effects of air pollution, J. Allergy Clin. Immun., 114, 1116–1123, doi:10.1016/j.jaci.2004.08.030, 2004. Bertram, A K., Ivanov, A V., Hunter, M., Molina, L T., and Molina, M J.: The reaction probability of OH on organic surfaces of tropospheric interest, J. Phys. Chem. A, 105, 9415–9421, 2001. Bey, I., Jacob, D J., Yantosca, R M., Logan, J A., Field, B D., Fiore, A M., Li, Q B., Liu, H. G Y., Mickley, L J., and Schultz, M G.: Global modeling of tropospheric chemistry with assimilated meteorology: Model description and evaluation, J. Geophys. Res.-Atmos., 106, 23073–23095, 2001. Bond, T C., Streets, D G., Yarber, K F., Nelson, S M., Woo, J H., and Klimont, Z.: A technology-based global inventory of black and organic carbon emissions from combustion, J. Geophys. Res.-Atmos., 109, D14203, doi:10.1029/2003JD003697, 2004. Brown, S S., Ryerson, T B., Wollny, A G., Brock, C A., Peltier, R., Sullivan, A P., Weber, R J., Dube, W P., Trainer, M., Meagher, J F., Fehsenfeld, F C., and Ravishankara, A R.: Variability in nocturnal nitrogen oxide processing and its role in regional air quality, Science, 311, 67–70, doi:10.1126/science.1120120, 2006. Chang, J S., Brost, R A., Isaksen, I S A., Madronich, S., Middleton, P., Stockwell, W R., and Walcek, C J.: A Three-Dimensional Eulerian Acid Deposition Model – Physical Concepts and Formulation, J. Geophys. Res.-Atmos., 92, 14681–14700, 1987. Cheung, J L., Li, Y Q., Boniface, J., Shi, Q., Davidovits, P., Worsnop, D R., Jayne, J T., and Kolb, C E.: Heterogeneous interactions of NO<sub>2</sub> with aqueous surfaces, J. Phys. Chem. A, 104, 2655–2662, 2002. Choi, W. and Leu, M T.: Nitric acid uptake and decomposition on black carbon (soot) surfaces: Its implications for the upper troposphere and lower stratosphere, J. Phys. Chem. A, 102, 7618–7630, 1998. Cosman, L M., Knopf, D A., and Bertram, A K.: N<sub>2</sub>O$_5$ reactive uptake on aqueous sulfuric acid solutions coated with branched and straight-chain insoluble organic surfactants, J. Phys. Chem. A, 112, 2386–2396, 2008. Crutzen, P J. and Arnold, F.: Nitric-acid cloud formation in the cold antarctic stratosphere – a major cause for the springtime ozone hole, Nature, 324, 651–655, 1986. Danckwerts, P V.: Absorption by simultaneous diffusion and chemical reaction into particles of various shapes and into falling drops, T. Faraday. Soc., 47, 1014–1023, 1951. Davis, J. M., Bhave, P. V., and Foley, K. M.: Parameterization of N<sub>2</sub>O$_5$ reaction probabilities on the surface of particles containing ammonium, sulfate, and nitrate, Atmos. Chem. Phys., 8, 5295–5311, 2008. Dentener, F J., Carmichael, G R., Zhang, Y., Lelieveld, J., and Crutzen, P J.: Role of mineral aerosol as a reactive surface in the global troposphere, J. Geophys. Res.-Atmos., 101, 22869–22889, 1996. Derwent, R G. and Jenkin, M E.: Hydrocarbons and the Long-range Transport of Ozone and PAN Across Europe, Atmos. Environ. A-Gen., 25, 1661–1678, 1991. Disselkamp, R S., Carpenter, M A., Cowin, J P., Berkowitz, C M., Chapman, E G., Zaveri, R A., and Laulainen, N S.: Ozone loss in soot aerosols, J. Geophys. Res.-Atmos., 105, 9767–9771, 2000. Donaldson, D J. and Vaida, V.: The Influence of Organic Films at the Air-Aqueous Boundary on Atmospheric Processes, Chem. Rev., 106, 1445–1461, doi:10.1021/cr040367c, 2006. Dymarska, M., Murray, B J., Sun, L M., Eastwood, M L., Knopf, D A., and Bertram, A.: Deposition ice nucleation on soot at temperatures relevant for the lower troposphere, J. Geophys. Res.-Atmos., 111, D04204, doi:10.1029/2005JD006627, 2006. EPA, U S.: 2006 Edition of the Drinking Water Standards and Health Advisories, US Environmental Protection Agency, Washington, DC, epa 822-r-06-013 edn., 18~pp., 2006a. EPA, U S.: Air Quality Criteria for Ozone and Related Photochemical Oxidants (Final), US Environmental Protection Agency, Washington, DC, epa/600/r-05/004af-cf edn., 821~pp., 2006b. Evans, M J. and Jacob, D J.: Impact of new laboratory studies of N<sub>2</sub>O$_5$ hydrolysis on global model budgets of tropospheric nitrogen oxides, ozone, and OH, Geophys. Res. Lett., 32, L09813, doi:10.1029/2005GL022469, 2005. Finlayson-Pitts, B J. and Pitts, J N.: Tropospheric air pollution: Ozone, airborne toxics, polycyclic aromatic hydrocarbons, and particles, Science, 276, 1045–1052, 1997. Finlayson-Pitts, B J. and Pitts, J N.: Chemistry of the Upper and Lower Atmosphere, Academic Press, San Diego, 969~pp., 2000. Franze, T., Weller, M G., Niessner, R., and Pöschl, U.: Enzyme immunoassays for the investigation of protein nitration by air pollutants, Analyst, 128, 824–831, doi:10.1039/b303132b, 2003. Franze, T., Weller, M G., Niessner, R., and Pöschl, U.: Protein nitration by polluted air, Environ. Sci. Technol., 39, 1673–1678, doi:10.1021/es0488737, 2005. Fuchs, N A. and Sutugin, A G.: High-dispersed aerosols, in: Topics in current aerosol research,, edited by: Hidy, G. M. and Brock, J. R., Pergamon, New York, 1971. Gerecke, A., Thielmann, A., Gutzwiller, L., and Rossi, M J.: The chemical kinetics of HONO formation resulting from heterogeneous interaction of NO<sub>2</sub> with flame soot, Geophys. Res. Lett., 25, 2453–2456, 1998. Grell, G A., Peckham, S E., Schmitz, R., McKeen, S A., Frost, G., Skamarock, W C., and Eder, B.: Fully coupled "online" chemistry within the WRF model, Atmos. Environ., 39, 6957–6975, 2005. Gross, S. and Bertram, A K.: Reactive Uptake of NO<sub>3</sub>, N<sub>2</sub>O$_5$, NO<sub>2</sub>, HNO<sub>3</sub>, and O<sub>3</sub> on Three Types of Polycyclic Aromatic Hydrocarbon Surfaces, J. Phys. Chem. A, 112, 3104–3113, 2008. Gross, S. and Bertram, A K.: Products and kinetics of the reactions of an alkane monolayer and a terminal alkene monolayer with NO<sub>3</sub> radicals, J. Geophys. Res.-Atmos., 114, D02307, doi:10.1029/2008JD010987, 2009. Hanson, D R. and Ravishankara, A R.: The reaction probabilities of ClONO<sub>2</sub> and N<sub>2</sub>O$_5$ on 40-percent to 75-percent sulfuric-acid-solutions, J. Geophys. Res.-Atmos., 96, 17307–17314, 1991. Hearn, J D. and Smith G D.: A mixed-phase relative rates \mboxtechnique for measuring aerosol reaction kinetics, Geophys. Res. Lett., 33, L17805, doi:10.1029/2006GL026963, 2006. Homann, K H.: Fullerenes and soot formation – New pathways to large particles in flames, Angew. Chem., Int. Ed, 37, 2435–2451, 1998. Kamm, S., Mohler, O., Naumann, K H., Saathoff, H., and Schurath, U.: The heterogeneous reaction of ozone with soot aerosol, Atmos. Environ., 33, 4651–4661, 1999. Kanakidou, M., Seinfeld, J. H., Pandis, S. N., Barnes, I., Dentener, F. J., Facchini, M. C., Van Dingenen, R., Ervens, B., Nenes, A., Nielsen, C. J., Swietlicki, E., Putaud, J. P., Balkanski, Y., Fuzzi, S., Horth, J., Moortgat, G. K., Winterhalter, R., Myhre, C. E. L., Tsigaridis, K., Vignati, E., Stephanou, E. G., and Wilson, J.: Organic aerosol and global climate modelling: a review, Atmos. Chem. Phys., 5, 1053–1123, 2005. Karagulian, F., Santschi, C., and Rossi, M. J.: The heterogeneous chemical kinetics of N<sub>2</sub>O$_5$ on CaCO<sub>3</sub> and other atmospheric mineral dust surrogates, Atmos. Chem. Phys., 6, 1373–1388, 2006. Kirchner, U., Scheer, V., and Vogt, R.: FTIR spectroscopic investigation of the mechanism and kinetics of the heterogeneous reactions of NO<sub>2</sub> and HNO<sub>3</sub> with soot, J. Phys. Chem. A, 104, 8908–8915, 2000. Kleffmann, J., Becker, K H., Lackhoff, M., and Wiesen, P.: Heterogeneous conversion of NO<sub>2</sub> on carbonaceous surfaces, Phys. Chem. Chem. Phys., 1, 5443–5450, 1999. Knopf, D A., Cosman, L M., Mousavi, P., Mokamati, S., and Bertram, A K.: A novel flow reactor for studying reactions on liquid surfaces coated by organic monolayers: Methods, validation, and initial results, J. Phys. Chem. A, 111, 11021–11032, 2007. Knopf, D A., Mak, J., Gross, S., and Bertram, A K.: Does atmospheric processing of saturated hydrocarbon surfaces by NO<sub>3</sub> lead to volatilization?, Geophys. Res. Lett., 33, L17816, doi:10.1029/2006GL026884, 2006. Kuhn, M., Builtjes, P J H., Poppe, D., Simpson, D., Stockwell, W R., Andersson-Skold, Y., Baart, A., Das, M., Fiedler, F., Hov, O., Kirchner, F., Makar, P A., Milford, J B., Roemer, M G M., Ruhnke, R., Strand, A., Vogel, B., and Vogel, H.: Intercomparison of the gas-phase chemistry in several chemistry and transport models, Atmos. Environ., 32, 693–709, 1998. Letzel, T., Pöschl, U., Rosenberg, E., Grasserbauer, M., and Niessner, R.: In-source fragmentation of partially oxidized mono- and polycyclic aromatic hydrocarbons in atmospheric pressure chemical ionization mass spectrometry coupled to liquid chromatography, Rapid Commun. Mass Sp., 13, 2456–2468, 1999a. Letzel, T., Rosenberg, E., Wissiack, R., Grasserbauer, M., and Niessner, R.: Separation and identification of polar degradation products of benzo[a]pyrene with ozone by atmospheric pressure chemical ionization-mass spectrometry after optimized column chromatographic clean-up, J. Chromatogr. A, 855, 501–514, 1999b. Letzel, T., Pöschl, U., Wissiack, R., Rosenberg, E., Grasserbauer, M., and Niessner, R.: Phenyl-modified reversed-phase liquid chromatography coupled to atmospheric pressure chemical ionization mass spectrometry: A universal method for the analysis of partially oxidized aromatic hydrocarbons, Anal. Chem., 73, 1634–1645, doi:10.1021/ac001079t, 2001. Massman, W J.: A review of the molecular diffusivities of H<sub>2</sub>O, CO<sub>2</sub>, CH<sub>4</sub>, CO, O<sub>3</sub>, SO<sub>2</sub>, NH<sub>3</sub>, N<sub>2</sub>O, NO, and NO<sub>2</sub> in air, O<sub>2</sub> and N<sub>2</sub> near STP, Atmos. Environ., 32, 1111–1127, 1998. Molina, M J., Tso, T L., Molina, L T., and Wang, F C Y.: Antarctic Stratospheric Chemistry of Chlorine Nitrate, Hydrogen Chloride and Ice – Release of Active Chlorine, Science, 238, 1253–1257, 1987. Molina, M J., Ivanov, A V., T rakhtenberg, S. and Molina, L T.: Atmospheric evolution of organic aerosol, Geophys. Res. Lett., 31, L22104, doi:10.1029/2004GL020910, 2004. Nienow, A M. and Roberts, J T.: Heterogeneous chemistry of carbon aerosols, Annu. Rev. Phys. Chem., 57, 105–128, doi:10.1146/annurev.physchem.57.032905.104525, 2006. Nishino, J.: Adsorption of water vapor and carbon dioxide at carboxylic functional groups on the surface of coal, Fuel, 80, 757–764, 2001. Osthoff, H D., Roberts, J M., Ravishankara, A R., Williams, E J., Lerner, B M., Sommariva, R., Bates, T S., Coffman, D., Quinn, P K., Dibb, J E., Stark, H., Burkholder, J B., Talukdar, R K., Meagher, J., Fehsenfeld, F C., and Brown, S S.: High levels of nitryl chloride in the polluted subtropical marine boundary layer, Nat. Geosci., 1, 324–328, doi:10.1038/ngeo177, 2008. Park, J H., Ivanov A V., and Molina, M J.: Effect of relative humidity on OH uptake by surfaces of atmospheric importance, J. Phys. Chem. A, 112, 6968–6977, 2008. Petters, M D., Prenni, A J., Kreidenweis, S M., DeMott, P J., Matsunaga, A., Lim, Y B., and Ziemann, P J.: Chemical aging and the hydrophobic-to-hydrophilic conversion of carbonaceous aerosol, Geophys. Res. Lett., 33, 1107–1118, 2006. Popovicheva, O B., Persiantseva, N M., Tishkova, V., Shonija, N K., and Zubareva, N A.: Quantification of water uptake by soot particles, Environ. Res. Lett., 3, 025009, doi:10.1088/1748-9326/3/2/025009, 2008. Pöschl, U.: Formation and decomposition of hazardous chemical components contained in atmospheric aerosol particles, J. Aerosol Med., 15, 203–212, 2002. Pöschl, U.: Atmospheric aerosols: Composition, transformation, climate and health effects, Angew. Chem., Int. Ed, 44, 7520–7540, doi:10.1002/anie.200501122, 2005. Pöschl, U., Letzel, T., Schauer, C., and Niessner, R.: Interaction of ozone and water vapor with spark discharge soot aerosol particles coated with benzo[a]pyrene: O<sub>3</sub> and H<sub>2</sub>O adsorption, benzo[a]pyrene degradation, and atmospheric implications, J. Phys. Chem. A, 105, 4029–4041, 2001. Pöschl, U., Rudich, Y., and Ammann, M.: Kinetic model framework for aerosol and cloud surface chemistry and gas-particle interactions - Part~1: General equations, parameters, and terminology, Atmos. Chem. Phys., 7, 5989–6023, 2007. Rogaski, C A., Golden, D M., and Williams, L R.: Reactive uptake and hydration experiments on amorphous carbon treated with NO<sub>2</sub>, SO<sub>2</sub>, O<sub>3</sub>, HNO<sub>3</sub>, and H<sub>2</sub>SO<sub>4</sub>, Geophys. Res. Lett., 24, 381–384, 1997. Rogge, W F., Mazurek, M A., Hildemann, L M., Cass, G R., and Simoneit, B R T.: Quantification of urban organic aerosols at a molecular-level – identification, abundance and seasonal-variation, Atmos. Environ. A-Gen., 27, 1309–1330, 1993. Rudich, Y.: Laboratory perspectives on the chemical transformations of organic matter in atmospheric particles, Chem. Rev., 103, 5097–5124, doi:10.1021/cr020508f, 2003. Rudich, Y., Donahue, N M., and Mentel, T F.: Aging of organic aerosol: Bridging the gap between laboratory and field studies, Annu. Rev. Phys. Chem., 58, 321–352, doi:10.1146/annurev.physchem.58.032806.104432, 2007. Saathoff, H., Naumann, K H., Riemer, N., Kamm, S., Mohler, O., Schurath, U., Vogel, H., and Vogel, B.: The loss of NO<sub>2</sub>, HNO<sub>3</sub>, NO<sub>3</sub>/N<sub>2</sub>O$_5$, and HO<sub>2</sub>/HOONO<sub>2</sub> on soot aerosol: A chamber and modeling study, Geophys. Res. Lett., 28, 1957–1960, 2001. Schwartz, S E.: NATO~ASI Series, chapter: Mass-transport considerations pertinent to aqueous phase reactions of gases in liquid-water clouds, Chemistry of Multiphase Atmospheric 15 Systems, Springer, Berlin, Germany, G6, 415~pp., 1986. Schwartz, S E. and Freiberg, J E.: Mass-transport limitation to the rate of reaction of gases in liquid droplets – Application to oxidation of SO<sub>2</sub> in aqueous-solutions, Atmos. Environ., 15, 1129–1144, 1981. Seinfeld, J H. and Pandis, S.: Atmospheric Chemistry and Physics: From Air Pollution to Climate Change, Wiley-Interscience, New York, 2006. Seisel, S., Börensen, C., Vogt, R., and Zellner, R.: Kinetics and mechanism of the uptake of N<sub>2</sub>O$_5$ on mineral dust at 298 K, Atmos. Chem. Phys., 5, 3423–3432, 2005. Shilling, J E., King, S M., Mochida, M., and Martin, S T.: Mass spectral evidence that small changes in composition caused by oxidative aging processes alter aerosol CCN properties, J. Phys. Chem. A, 111, 3358–3368, doi:10.1021/jp068822r, 2007. Smith, D M. and Chughtai, A R.: Reaction kinetics of ozone at low concentrations with n-hexane soot, J. Geophys. Res.-Atmos., 101, 19607–19620, 1996. Solomon, S., Mills, M., Heidt, L E., Pollock, W H., and Tuck, A F.: On the evaluation of ozone depletion potentials, J. Geophys. Res.-Atmos., 97, 825–842, 1992. Stemmler, K., Ammann, M., Donders, C., Kleffmann, J., and George, C.: Photosensitized reduction of nitrogen dioxide on humic acid as a source of nitrous acid, Nature, 440, 195–198, doi:10.1038/nature04603, 2006. Stephens, S., Rossi, M J., and Golden, D M.: The heterogeneous reaction of ozone on carbonaceous surfaces, Int. J. Chem. Kinet., 18, 1133–1149, 1986. Stockwell, W R., Middleton, P., Chang, J S., and Tang, X Y.: The 2nd generation regional acid deposition model chemical mechanism for regional air-quality modeling, J. Geophys. Res.-Atmos., 95, 16343–16367, 1990. Stockwell, W R., Kirchner, F., Kuhn, M., and Seefeld, S.: A new mechanism for regional atmospheric chemistry modeling, J. Geophys. Res.-Atmos., 102, 25847–25879, 1997. Tabor, K., Gutzwiller, L., and Rossi, M J.: Heterogeneous Chemical-Kinetics of NO<sub>2</sub> on Amorphous-Carbon at Ambient-Temperature, J. Phys. Chem., 98, 6172–6186, 1994. Thomas, E R., Frost, G J., and Rudich, Y.: Reactive uptake of ozone by proxies for organic aerosols: Surface-bound and gas-phase products, J. Geophys. Res.-Atmos., 106, 3045–3056, 2001. Tie, X., Brasseur, G., Emmons, L., Horowitz, L., and Kinnison, D.: Effects of aerosols on tropospheric oxidants: A global model study, J. Geophys. Res.-Atmos., 106, 22931–22964, 2001. Tie, X., Madronich, S., Li, G H., Ying, Z., Zhang, R., Garcia, A R., Lee-Taylor, J., and Liu, Y.: Characterizations of chemical oxidants in Mexico City: A regional chemical dynamical model (WRF-Chem) study, Atmos. Environ., 41, 1989–2008, 2007. Van~Gulijk, C., Marijnissen, J C M., Makkee, M., Moulijn, J A., and Schmidt-Ott, A.: Measuring diesel soot with a scanning mobility particle sizer and an electrical low-pressure impactor: performance assessment with a model for fractal-like agglomerates, J. Aerosol. Sci., 35, 633–655, doi:10.1016/j.jaerosci.2003.11.004, 2004. Vogel, B., Vogel, H., Kleffmann, J., and Kurtenbach, R.: Measured and simulated vertical profiles of nitrous acid – Part~II, Model simulations and indications for a photolytic source, Atmos. Environ., 37, 2957–2966, doi:10.1016/S1352-2310(03)00243-7, 2003.