Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 9 1 2009 10.5194/acp-9-271-2009 http://www.atmos-chem-phys.net/9/271/2009/ http://www.atmos-chem-phys.net/9/271/2009/acp-9-271-2009.html http://www.atmos-chem-phys.net/9/271/2009/acp-9-271-2009.pdf 271 285 2009-01-14 Emissions of volatile organic compounds inferred from airborne flux measurements over a megacity T. Karl tomkarl@ucar.edu E. Apel A. Hodzic D. D. Riemer D. R. Blake C. Wiedinmyer National Center for Atmospheric Research, Boulder, CO, USA University of Miami, Miami, FL, USA University of California, Irvine, CA, USA Toluene and benzene are used for assessing the ability to measure disjunct eddy covariance (DEC) fluxes of Volatile Organic Compounds (VOC) using Proton Transfer Reaction Mass Spectrometry (PTR-MS) on aircraft. Statistically significant correlation between vertical wind speed and mixing ratios suggests that airborne VOC eddy covariance (EC) flux measurements using PTR-MS are feasible. City-median midday toluene and benzene fluxes are calculated to be on the order of 14.1±4.0 mg/m²/h and 4.7±2.3 mg/m²/h, respectively. For comparison the adjusted CAM2004 emission inventory estimates toluene fluxes of 10 mg/m²/h along the footprint of the flight-track. Wavelet analysis of instantaneous toluene and benzene measurements during city overpasses is tested as a tool to assess surface emission heterogeneity. High toluene to benzene flux ratios above an industrial district (e.g. 10–15 g/g) including the International airport (e.g. 3–5 g/g) and a mean flux (concentration) ratio of 3.2±0.5 g/g (3.9±0.3 g/g) across Mexico City indicate that evaporative fuel and industrial emissions play an important role for the prevalence of aromatic compounds. Based on a tracer model, which was constrained by BTEX (BTEX– Benzene/Toluene/Ethylbenzene/m, p, o-Xylenes) compound concentration ratios, the fuel marker methyl-tertiary-butyl-ether (MTBE) and the biomass burning marker acetonitrile (CH₃CN), we show that a combination of industrial, evaporative fuel, and exhaust emissions account for >87% of all BTEX sources. Our observations suggest that biomass burning emissions play a minor role for the abundance of BTEX compounds in the MCMA (2–13%). % vor jede Referenz Andreae, M. O. and Merlet, P.: Emission of trace gases and aerosols from biomass burning, Global Biogeochem. Cy., 15, 955–966, 2001. % vor jede Referenz Apel, E. C., Hills, A. J., Flocke, F., Zheng, W., Fried, A., Weibring, P., McKenna, D., Emmons, L., Orlando, J., Karl, T., Campos, T., Riemer, D. D., Atlas, E., Blake, D., Olson, J., Chen, G., Crawford, J., and Sive, B.: Observations of volatile organic compounds downwind of Mexico City during MIRAGE-MEX, Eos Trans. AGU, 88(52), Fall Meet. Suppl., Abstract A41F-02, 2007. % vor jede Referenz Apel, E. C., Hills, A. J., Lueb, R., Zindel, S., Eisele, S. and Riemer, D. D.: A Fast-GC/MS system to measure C2 to C4 carbonyls, and methanol aboard aircraft, J. Geophys. Res., 108, 8794, doi:10.1029/2002JD003199, 2003. % vor jede Referenz Arellano Jr., A. F., Raeder, K., Anderson, J. L., Hess, P. G., Emmons, L. K., Edwards, D. P., Pfister, G. G., Campos, T. L., and Sachse, G. W.: Evaluating model performance of an ensemble-based chemical data assimilation system during INTEX-B field mission, Atmos. Chem. Phys., 7, 5695–5710, 2007. % vor jede Referenz Atkinson, R., Carter, W. P. L., Darnall, K. R., Winer, A. M., and Pitts Jr., J. N.: A smog chamber and modeling study of the gas phase NOx-air photooxidation of toluene and the cresols, Int. J. Chem. Kinet., 12, 779–836, 1980. % vor jede Referenz Atkinson, R. and Arey, J.: Atmospheric degradation of volatile organic compounds, Chem. Rev., 103, 4605–4638, 2003. % vor jede Referenz Blake, D. and Rowland, F. S.: Urban leakage of liquefied Petroleum Gas and Its Impact on Mexico City Air Quality, Science, 269, 953–956, 1995. % vor jede Referenz CAM01: Comision Ambiental Metropolitana: Inventario de emisiones a la atmosfera, zona metropolitana del valle Mexico, 1998, Mexico City, 2001. % vor jede Referenz CAM04: Comision Ambiental Metropolitana: Inventario de Emisiones 2002 de la Zona Metropolitana del Valle de Mexico, Mexico, 2004. % vor jede Referenz DeCarlo, P. F., Dunlea, E. J., Kimmel, J. R., Aiken, A. C., Sueper, D., Crounse, J., Wennberg, P. O., Emmons, L., Shinozuka, Y., Clarke, A., Zhou, J., Tomlinson, J., Collins, D. R., Knapp, D., Weinheimer, A. J., Montzka, D. D., Campos, T., and Jimenez, J. L.: Fast airborne aerosol size and chemistry measurements above Mexico City and Central Mexico during the MILAGRO campaign, Atmos. Chem. Phys., 8, 4027–4048, 2008. % vor jede Referenz de Gouw, J. A., Middlebrook, A. M., Warneke, C., Goldan, P. D., Kuster, W. C., Roberts, J. M., Fehsenfeld, F. C., Worsnop, D. R., Canagaratna, M. R., Pszenny, A. A. P., Keene, W. C., Marchewka, M., Bertman, S. B., and Bates, T. S.: Budget of organic carbon in a polluted atmosphere: Results from the New England Air Quality Study in 2002, J. Geophys. Res., 110, D16305, doi:10.1029/2004JD005623, 2005. % vor jede Referenz de Gouw, J. A., Brock, C. A., Atlas, E. L., Bates, T. S., Fehsenfeld, F. C., Goldan, P. D., Holloway, J. S., Kuster, W. C., Lerner, B. M., Matthew, B. M., Middlebrook, A. M., Onasch, T. B., Peltier, R. E., Quinn, P. K., Senff, C. J., Stohl, A., Sullivan, A. P., Trainer, M., Warneke, C., Weber, R. J., and Williams, E. J.: Sources of particulate matter in the northeastern United States in summer: 1. Direct emissions and secondary formation of organic matter in urban plumes, J. Geophys. Res., 113, D08301, doi:10.1029/2007JD009243, 2008. % vor jede Referenz de Gouw, J. A. and Warneke, C.: Measurements of volatile organic compounds in the Earth's atmosphere using proton-transfer-reaction mass spectrometry, Mass Spectrom. Rev., 26, 223–257, 2007. % vor jede Referenz Doran, J. C., Barnard, J. C., Arnott, W. P., Cary, R., Coulter, R., Fast, J. D., Kassianov, E. I., Kleinman, L., Laulainen, N. S., Martin, T., Paredes-Miranda, G., Pekour, M. S., Shaw, W. J., Smith, D. F., Springston, S. R., and Yu, X.-Y.: The T1-T2 study: evolution of aerosol properties downwind of Mexico City, Atmos. Chem. Phys., 7, 1585–1598, 2007. % vor jede Referenz Faloona, I., Lenschow, D. H., Campos, T., Stevens, B., van Zanten, M., Blomquist, B., Thornton, D., Bandy, A., and Gerber, H.: Observations of entrainment in eastern Pacific marine stratocumulus using three conserved scalars, J. Atmos. Sci., 62, 3268–3285, 2005. % vor jede Referenz Fast, J. D., Gustafson, W. I., Easter, R. C., Zaveri, R. A., Barnard, J. C., Chapman, E. G., Grell, G. A., and Peckham, S. E.: Evolution of ozone, particulates, and aerosol direct radiative forcing in the vicinity of Houston using a fully coupled meteorology-chemistry-aerosol model, J. Geophys. Res., 111, D21305, doi:10.1029/2005JD006721, 2006. % vor jede Referenz Fast, J. D., de Foy, B., Acevedo Rosas, F., Caetano, E., Carmichael, G., Emmons, L., McKenna, D., Mena, M., Skamarock, W., Tie, X., Coulter, R. L., Barnard, J. C., Wiedinmyer, C., and Madronich, S.: A meteorological overview of the MILAGRO field campaigns, Atmos. Chem. Phys., 7, 2233–2257, 2007. % vor jede Referenz Fortner, E. C., Zheng, J., Zhang, R., Knighton, W. B., and Molina, L.: Measurements of volatile organic compounds using proton transfer reaction - mass spectrometry during the MILAGRO 2006 Campaign, Atmos. Chem. Phys. Discuss., 8, 11821–11851, 2008. % vor jede Referenz Gerstle, T., Virag, P., Wade, M. D., and Brown, P. P.: Aircraft Engine and Auxiliary Power Unit Emissions Testing: Final \mboxReport Addendum F119-PW-100 Engine Emissions Testing Report, IERA-RS-BR-SR-2002-0006, Airforce Institute for Environment, Safety and Occupational Health Risk Analysis, Risk Analysis Directorate, Environmental Analysis Division, Brooks Air Force Base, USA, 1–251, 2002. % vor jede Referenz Graus, M., Hansel, A., Wisthaler, A., Lindinger, C., Forkel, R., Hauff, K., Klauer, M., Pfichner, A., Rappengluck, B., Steigner, D., and Steinbrecher, R.: A relaxed-eddy-accumulation method for the measurement of isoprenoid canopy-fluxes using an online gas-chromatographic technique and PTR-MS simultaneously, Atmos. Environ., 40, S43–S54, 2006. % vor jede Referenz Guenther, A. and Hills, A. J.: Eddy covariance measurement of isoprene fluxes, J. Geophys. Res., 103, 13, 13145–13152, 1998. % vor jede Referenz Guenther, A., Karl, T., Harley, P., Wiedinmyer, C., Palmer, P. I., and Geron, C.: Estimates of global terrestrial isoprene emissions using MEGAN (Model of Emissions of Gases and Aerosols from Nature), Atmos. Chem. Phys., 6, 3181–3210, 2006. % vor jede Referenz Hansel, A., Jordan, A., Warneke, C., Holzinger, R., and Lindinger, W.: Improved detection limit of the proton-transfer reaction mass spectrometer: on-line monitoring of volatile organic compounds at mixing ratios of a few pptv, Rapid Commun. Mass Sp., 12, 871–875, 1998. % vor jede Referenz Holzinger, R., Jordan, A., Hansel, A., and Lindinger, W.: Automobile Emissions of Acetonitrile: Assessment of its Contribution to the Global Source, J. Atmos. Chem., 38, 187–193, 2001. % vor jede Referenz Jobson, B. T., Berkowitz, C. M., Kuster, W. C., Goldan, P. D., Williams, E. J., Fesenfeld, F. C., Apel, E. C., Karl, T., Lonneman, W. A., and Riemer, D.: Hydrocarbon source signatures in Houston, Texas: Influence of the petrochemical industry, J. Geophys. Res., 109, D24305, doi:10.1029/2004JD004887, 2004. Jobson, B. T., Alexander, M. L., Maupin, G. D., and Muntean, G. G.: On-line analysis of organic compounds in diesel exhaust using a proton transfer reaction mass spectrometer, Int. J. Mass Spectrom., 245, 78–89, 2005. % vor jede Referenz Kaimal, J. C., Izumi, Y., Wyngaard, J. C., and Cote, R.: Spectral characteristics of surface-layer turbulence, Q. J. Roy. Meteor. Soc., 98, 563–566, 1972. % vor jede Referenz Karl, T., Jobson, T., Kuster, W. C., Williams, E., Stutz, J., Shetter, R., Hall, S. R., Goldan, P., Fehsenfeld, F., and Lindinger, W.: Use of proton-transfer-reaction mass spectrometry to characterize volatile organic compound sources at the La Porte super site during the Texas Air Quality Study 2000, J. Geophys. Res., 108, 4508, doi:10.1029/2002JD003333, 2003. % vor jede Referenz Karl, T., Guenther, A., Jordan, A., Fall, R., and Lindinger, W.: Eddy covariance measurments of biogenic oxygenated VOC emissions from hay harvesting, Atmos. Environ., 35, 491–495, 2001. % vor jede Referenz Karl, T. G., Spirig, C., Rinne, J., Stroud, C., Prevost, P., Greenberg, J., Fall, R., and Guenther, A.: Virtual disjunct eddy covariance measurements of organic compound fluxes from a subalpine forest using proton transfer reaction mass spectrometry, Atmos. Chem. Phys., 2, 279–291, 2002. % vor jede Referenz Kleinman, L. I.: The dependence of tropospheric ozone production rate on ozone precursors, Atmos. Environ., 39, 575–586, 2005. % vor jede Referenz Holzinger, R., Lee, A., McKay, M., and Goldstein, A. H.: Seasonal variability of monoterpene emission factors for a ponderosa pine plantation in California, Atmos. Chem. Phys., 6, 1267–1274, 2006. % vor jede Referenz Lei, W., de Foy, B., Zavala, M., Volkamer, R., and Molina, L. T.: Characterizing ozone production in the Mexico City Metropolitan Area: a case study using a chemical transport model, Atmos. Chem. Phys., 7, 1347–1366, 2007. % vor jede Referenz Lemieux, P. M., Lutes, C. C., and Santoianni, D. A.: Emissions of organic air toxics from open burning: a comprehensive review, Prog. Energ. Combust., 30, 1–32, 2004. % vor jede Referenz Lenschow, D. H., Pearson, R., and Stankov, B. B.: Estimating the ozone budget in the boundary layer by use of aircraft measurements of ozone eddy flux and mean concentration, J. Geophys. Res., 86, 7291–7297, 1981. % vor jede Referenz Lenschow, D. H., Mann, J., and Kristensen, L.: How long is long enough when measuring fluxes and other turbulence statistics, J. Atmos. Ocean. Tech., 11, 661–673, 1994. % vor jede Referenz Lindinger, W., Jordan, A., and Hansel, A.: Proton-transfer-reaction mass spectroscopy (PTR-MS): on-line monitoring of volatile organic compounds at pptv levels, Chem. Soc. Rev., 27, 347–534, 1998. % vor jede Referenz Liu, S. C., Trainer, M., Fehsenfeld, F. C., Parrish, D. D., Williams, E. J., Fahey, D. W., Hubler, G., and Murphy, P. C.: Ozone production in the rural troposphere and the implications for regional and global ozone distributions, J. Geophys. Res., 92, 4191–4207, 1987. % vor jede Referenz Mann, J. and Lenschow, D. H: Errors in airborne flux measurements, J. Geophys. Res., 99, 14519–14526, 1994. % vor jede Referenz Mauder, M., Desjardins, R. L., and MacPherson, I.: Scale analysis of airborne flux measurements over heterogeneous terrain in a boreal ecosystem, J. Geophys. Res., 112, D13112, doi:10.1029/2006JD008133, 2007. % vor jede Referenz Millet, D. B., Goldstein, A. H., Allan, J. D., Bates, T. S., Boudries, H., Bower, K. N., Coe, H., Ma, Y., McKay, M., Quinn, P. K., Sullivan, A., Weber, R. J., and Worsnop, D. R.: Volatile organic compound measurements at Trinidad Head, California, during ITCT 2K2: Analysis of sources, atmospheric composition, and aerosol residence times, J. Geophys. Res., 109, D23S16, doi:10.1029/2003JD004026, 2004. % vor jede Referenz Molina, L. T., Madronich, S., Gaffney, J. S., and Singh, H. B.: Overview of MILAGRO/INTEX-B Campaign, IGAC Newsletter, 38, 2–15, 2008. % vor jede Referenz Nemitz, E., Hargreaves, K. J., McDonald, A. G., Dorsey, J. R., and Fowler, D.: Meteorological measurements of the urban heat budget and CO₂ emissions on a city scale, Environ. Sci. Technol., 36, 3139–3146, 2002. % vor jede Referenz Ng, N. L., Kroll, J. H., Chan, A. W. H., Chhabra, P. S., Flagan, R. C., and Seinfeld, J. H.: Secondary organic aerosol formation from m-xylene, toluene, and benzene, Atmos. Chem. Phys., 7, 3909–3922, 2007. % vor jede Referenz Olivier, J. G. J, Bouwman, A. F., Berdowski, J. J. M., Veldt, C., Bloos, J. P. J., Visschedijk, A. J. H., van der Maas, C. W. M., and Zandveld, P. Y. J.: Sectoral emission inventories of greenhouse gases for 1990 on a per country basis as well as on 1x1 degree, Environ. Sci. Policy, 2, 241–264, 1999. % vor jede Referenz Olivier, J. G. J., Van Aardenne, J. A., Dentener, F., Ganzeveld, L., and Peters, J. A. H. W.: Recent trends in global greenhouse gas emissions: regional trends and spatial distribution of key sources, in: Non-CO2 Greenhouse Gases (NCGG-4), edited by: van Amstel, A., 325–330, Millpress, Rotterdam, ISBN 90-5966-043-9, 2005. % vor jede Referenz Pierce, T., Geron, C., Bender, L., Dennis, R., Tonnesen, G., and Guenther, A.: Influence of increased isoprene emissions on regional ozone modeling, J. Geophys. Res., 103, 25611–25629, 1998. % vor jede Referenz Pressley, S., Lamb, B., Westberg, H., and Vogel, C.: Relationships among canopy scale energy fluxes and isoprene flux derived from long-term, seasonal eddy covariance measurements over a hardwood forest, Agr. Forest Meteorol., 136, 188–202, 2006. % vor jede Referenz Rinne, H. J. I., Guenther, A. B., Warneke, C., de Gouw, J. A., and Luxembourg, S. L.: Disjunct eddy covariance technique for trace gas flux measurements, Geophys. Res. Lett., 28, 3139–3142, 2001. % vor jede Referenz Rinsky, R. A., Smith, A. B., Hornung, R., Filloon, T. G., Young, R. J., Okun, A. H., and Landrigan, P. J.: Benzene and Leukemia – An epidemiologic risk assessment, New Engl. J. Med., 316, 1044–1050, 1987. % vor jede Referenz Rogers, T. M., Grimsrud, E. R., Herndon, S. C., Jayne, J. T., Kolb, C. E., Allwine, E., Westberg, H., Lamb, B. K., Zavala, M., Molina, L. T., Molina, M. J., and Knighton, W. B.: On-road measurements of volatile organic compounds in the Mexico City metropolitan area using proton transfer reaction mass spectrometry, Int. J. Mass Spectrom., 252, 26–37, 2006. % vor jede Referenz Sato, K., Hatakeyama, S., and Imamura, T.: Secondary organic aerosol formation during the photooxidation of toluene: NO_x dependence of chemical composition, J. Phys. Chem.-US A, 111, 9796–9808, 2007. % vor jede Referenz Shaw, W. J., Pekour, M. S., Coulter, R. L., Martin, T. J., and Walters, J. T.: The daytime mixing layer observed by radiosonde, profiler, and lidar during MILAGRO, Atmos. Chem. Phys. Discuss., 7, 15025–15065, 2007. % vor jede Referenz Sillman, S.: The use of NO_y, H₂O₂, and HNO₃ as indicators for ozone-NO$_x$-hydrocarbon sensitivity in urban locations, J. Geophys. Res., 100, 14175–14188, 1995. % vor jede Referenz SMAGDF: Inventario de emisiones de contaminantes criterio de la Zona Metropolitana del Valle de México, Secretaría del Medio Ambiente del Gobierno del Distrito Federal, 2008. % vor jede Referenz Spirig, C., Neftel, A., Ammann, C., Dommen, J., Grabmer, W., Thielmann, A., Schaub, A., Beauchamp, J., Wisthaler, A., and Hansel, A.: Eddy covariance flux measurements of biogenic VOCs during ECHO 2003 using proton transfer reaction mass spectrometry, Atmos. Chem. Phys., 5, 465–481, 2005. % vor jede Referenz Stephens, S., Madronich, S., Wu, F., Olson, J. B., Ramos, R., Retama, A., and Muñoz, R.: Weekly patterns of México City's surface concentrations of CO, NO_x, PM$_10$ and O₃ during 1986–2007, Atmos. Chem. Phys., 8, 5313–5325, 2008. % vor jede Referenz Stull, R. B.: An Introduction to Boundary Layer Meteorology, Kluwer Acad., Norwell, Mass., Dordrecht, 427–428, 1988. % vor jede Referenz Thomas, C. and Foken, T.: Detection of long-term coherent exchange over spruce forest using wavelet analysis, Theor. Appl. Climatol., 80, 91–104, 2005. % vor jede Referenz Tie, X. X., Madronich, S., Li, G. H., Ying, Z. M., Zhang, R. Y., Garcia, A. R., Lee-Taylor, J., and Liu, Y. B.: Characterizations of chemical oxidants in Mexico City: A regional chemical dynamical model (WRF-Chem) study, Atmos. Environ., 41, 1989–2008, 2007. % vor jede Referenz Torrence, C. and Compo, G. P.: A practical guide to wavelet analysis, B. Am. Meteorol. Soc., 79, 61–78, 1998. % vor jede Referenz Vega, E., Mugica, V., Carmona, R., and Valencia, E.: Hydrocarbon source apportionment in Mexico City using the chemical mass balance receptor model, Atmos. Environ., 34, 4121–4129, 2000. % vor jede Referenz Velasco, E., Lamb, B., Pressley, S., Allwine, E., Westberg, H., Jobson, T., Alexander, M., Prazeller, P., Molina, L., and Molina, M.: Flux measurements of volatile organic compounds from an urban landscape, Geophys. Res. Lett., 32, L20802, doi:10.1029/2005GL023356, 2005. % vor jede Referenz Velasco, E., Lamb, B., Westberg, H., Allwine, E., Sosa, G., Arriaga-Colina, J. L., Jobson, B. T., Alexander, M. L., Prazeller, P., Knighton, W. B., Rogers, T. M., Grutter, M., Herndon, S. C., Kolb, C. E., Zavala, M., de Foy, B., Volkamer, R., Molina, L. T., and Molina, M. J.: Distribution, magnitudes, reactivities, ratios and diurnal patterns of volatile organic compounds in the Valley of Mexico during the MCMA 2002 & 2003 field campaigns, Atmos. Chem. Phys., 7, 329–353, 2007. % vor jede Referenz Volkamer, R., Jimenez, J. L., San Martini, D., Molina, L. T., Worsnop, D. R., and Molina, M. J.: Secondary organic aerosol formation from anthropogenic air pollution: Rapid and higher than expected, Geophys. Res. Lett., 33, L17811, doi:10.1029/2006GL026899, 2006. % vor jede Referenz Volkswagen AG: Nicht limitierte Automobil-Abgaskomponenten, Report, Forschung Physik.-chem. Messtechnik, Wolfsburg, 1988. % vor jede Referenz Warneke, C., van der Veen, C., Luxembourg, S., de Gouw, J. A., and Kok, A.: Measurements of benzene and toluene in ambient air using proton-transfer-reaction mass spectrometry: calibration, humidity dependence, and field intercomparison, Int. J. Mass Spectrom., 207, 167–182, 2001. % vor jede Referenz Warneke, C., McKeen, S. A., de Gouw, J. A., Goldan, P. D., Kuster, W. C., Holloway, J. S., Williams, E. J., Lerner, B. M., Parrish, D. D., Trainer, M., Fehsenfeld, F. C., Kato, S., Atlas, E. L., Baker, A., and Blake, D. R.: Determination of urban volatile organic compound emission ratios and comparison with and emissions database, J. Geophys. Res., 112, D10S47, doi:10.1029/2006JD007930, 2007. % vor jede Referenz Weber, R. J., Sullivan, A. P., Peltier, R. E., Russell, A., Yan, B., Zheng, M., deGouw, J., Warneke, C., Brock, C., Holloway, J. S., Atlas, E. L., and Edgerton, E.: A study of secondary organic aerosol formation in the anthropogenic-influenced southeastern United States, J. Geophys. Res., 112, D13302, doi:10.1029/2007JD008408, 2007. % vor jede Referenz Weil, J. C. and Horst, T. W.: Footprint estimates for atmospheric flux measurements in the convective boundary layer, in: Precipitation Scavenging and Atmosphere-Surface Exchange, edited by: Schwartz, S. E. and Slinn, W. G. N., Hemisphere Publishing, 2, 717–728, 1992. % vor jede Referenz Wert, B. P., Trainer, M., Fried, A., Ryerson, T. B., Henry, B., Potter, W., Angevine, W. M., Atlas, E., Donnelly, S. G., Fehsenfeld, F. C., Frost, G. J., Goldan, P. D., Hansel, A., Holloway, J. S., Hubler, G., Kuster, W. C., Nicks, D. K., Neuman, J. A., Parrish, D. D., Schauffler, S., Stutz, J., Sueper, D. T., Wiedinmyer, C., and Wisthaler, A.: Signatures of terminal alkene oxidation in airborne formaldehyde measurements during TexAQS 2000, J. Geophys. Res., 108, 4104, doi:10.1029/2002JD002502, 2003. % vor jede Referenz West, J. J., Zavala, M. A., Molina, L. T., Molina, M. J., San Martini, F., McRae, G. J., Sosa-Iglesias, G., and Arriaga-Colina, J. L.: Modeling ozone photochemistry and evaluation of hydrocarbon emissions in the Mexico City metropolitan area, J. Geophys. Res., 109, D19312, doi:10.1029/2004JD004614, 2004. % vor jede Referenz Wiedinmyer, C., Quayle, B., Geron, C., Belote, A., McKenzie, D., Zhange, X. Y., O'Neill, W., and Wynne, K. K.: Estimating emissions from fires in North America for air quality modeling, Atmos. Environ., 40, 3419–3432, 2006. % vor jede Referenz Yokelson, R. J., Karl, T., Artaxo, P., Blake, D. R., Christian, T. J., Griffith, D. W. T., Guenther, A., and Hao, W. M.: The Tropical Forest and Fire Emissions Experiment: overview and airborne fire emission factor measurements, Atmos. Chem. Phys., 7, 5175–5196, 2007. % vor jede Referenz Yokelson, R. J., Urbanski, S. P., Atlas, E. L., Toohey, D. W., Alvarado, E. C., Crounse, J. D., Wennberg, P. O., Fisher, M. E., Wold, C. E., Campos, T. L., Adachi, K., Buseck, P. R., and Hao, W. M.: Emissions from forest fires near Mexico City, Atmos. Chem. Phys., 7, 5569–5584, 2007. % vor jede Referenz Zavala, M., Herndon, S. C., Slott, R. S., Dunlea, E. J., Marr, L. C., Shorter, J. H., Zahniser, M., Knighton, W. B., Rogers, T. M., Kolb, C. E., Molina, L. T., and Molina, M. J.: Characterization of on-road vehicle emissions in the Mexico City Metropolitan Area using a mobile laboratory in chase and fleet average measurement modes during the MCMA-2003 field campaign, Atmos. Chem. Phys., 6, 5129–5142, 2006. % vor jede Referenz Zaveri, R. A., Easter, R. C., Fast, J. D., and Peters, L. K.: Model for Simulating Aerosol Interactions and Chemistry (MOSAIC), J. Geophys. Res., 113, D13204, doi:10.1029/2007jd008782, 2008. % vor jede Referenz Zhao, W. X., Hopke, P. K., and Karl, T.: Source identification of volatile organic compounds in Houston, Texas, Environ. Sci. Technol., 38, 1338–1347, 2004.