Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 7 4 2007 10.5194/acpd-7-12751-2007 http://www.atmos-chem-phys-discuss.net/7/12751/2007/ http://www.atmos-chem-phys-discuss.net/7/12751/2007/acpd-7-12751-2007.html http://www.atmos-chem-phys-discuss.net/7/12751/2007/acpd-7-12751-2007.pdf 12751 12779 2007-08-30 Vertical distribution of ozone and VOCs in the low boundary layer of Mexico City E. Velasco evelasco@mce2.org C. Márquez E. Bueno R. M. Bernabé A. Sánchez O. Fentanes H. Wöhrnschimmel B. Cárdenas A. Kamilla S. Wakamatsu L. T. Molina Molina Center for the Energy and the Environment (MCE2), La Jolla, CA, USA Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA Centro Nacional de Investigación y Capacitación Ambiental del Instituto Nacional de Ecología (CENICA-INE), D.F., México Japanese International Cooperation Agency (JICA), Tokyo, Japan Atmospheric Environmental Science Laboratory, Faculty of Agriculture, Ehime University, Ehime, Japan The evolution of ozone and 13 volatile organic compounds (VOCs) in the boundary layer of Mexico City was investigated during 2000–2004 to improve our understanding of the complex interactions between those trace gases and meteorological variables, and their influence on the air quality of a polluted megacity. A tethered balloon, fitted with electrochemical and meteorological sondes, was used to obtain detailed vertical profiles of ozone and meteorological parameters up to 1000 m above ground during part of the diurnal cycle (02:00–18:00 h). VOCs samples were collected up to 200 m by pumping air to canisters with a Teflon tube attached to the tether line. Overall, features of these profiles were found to be consistent with a simple picture of nighttime trapping of ozone in an upper residual layer and of VOCs in a shallow unstable layer above the ground. After sunrise an ozone balance is determined by photochemical production, entrainment from the upper residual layer and destruction by titration with NO, delaying the ground-level ozone rise by 2 h. The subsequent evolution of the conductive boundary layer and vertical distribution of pollutants are discussed in terms of the energy balance, the presence of turbulence and the atmospheric stability. Aneja, V. P., Mathur, R., Arya, S. P., Li, Y., Murray, G. C., and Manuszak, T. L.: Coupling the vertical distribution of ozone in the atmospheric boundary layer, Environ. Sci. Technol., 34, 2324–2329, 2000. Arya, S. P.: Introduction to micrometeorology. Academic Press, Great Britain, 2001. Barnes, R. A., Bandy, A. R., and Torres, A. L.: Electrochemical concentration cell ozonosonde accuracy and precision, J. Geophys. Res., 90, 7881–7887, 1985. Baumbach, G. and Vogt, U.: Influence of inversion layers on the distribution of air pollutants in urban areas, Water, Air, and Soils Pollution: Focus, 3, 65–76, 2003. Chen, C. L., Tsuang, B. J., Tu, C. Y., Cheng, W. L., and Lin, M. D.: Wintertime vertical profiles of air pollutants over a suburban area in central Taiwan, Atmos. Environ., 36, 2049–2059, 2002. de Foy, B., Caetano, E., Magaña, V., Zitacuaro, A., Cardenas, B., Retama, A., Ramos, R., Molina, L. T., and Molina, M. J.: Mexico City basin wind circulation during the MCMA-2003 field campaign, Atmos. Chem. Phys., 5, 2267–2288, 2005. Doran, J. C., Abbott, S., Archuleta, J., Bian, X., Chow, J., et al.: The IMADA-AVER boundary layer experiment in the Mexico City area, Bull. Amer. Meteorol. Soc., 79, 2497–2508, 1998. Glaser, K., Vogt, U., Baumbach, G., Voz-Thomas, A., and Geiss, H.: Vertical profiles of O₃, NO₂, NOx, VOC, and meteorological parameters during the Berlin Ozone Experiment (BERLIOZ) campaign, J. Geophys. Res., 108(D4), 8253, doi:10.1029/2002JD002475, 2003. Grant, R. H. and Wong, K. L.: Ozone profiles over a suburban neighborhood, Atmos. Environ., 33, 51–63, 1999. Greenberg, J. P., Guenther, A., Zimmerman, P., Baugh, W., Geron, C., Davis, K., Helmig, D., and Klinger, L. F.: Tethered balloon measurements of biogenic VOCs in the atmospheric boundary layer, Atmos. Environ., 33, 855–867, 1999. Lee, S. M., Fernando, H. J .S., Princevac, M., Zajic, D., Sinesi, M., Mcculley, J. L., and Anderson, J.: Transport and diffusion of ozone in the nocturnal and morning planetary boundary layer of the Phoenix Valley, Environ. Fluid Mech., 3, 331–362, 2003. Maeda, T., Tanabe, K., and Morita, M.: Long-term monitoring of hazardous volatile organic air pollutants using capillary chromatography GC-MS LC- GC, The Magazine of Separation Science, 16, 478–486, 1998. Molina, L. T., Kolb, C. E., de Foy, B., Lamb B. K., Brune, W. H., Jiménez, J. L., Ramos-Villegas, R., Sarmiento, J., Paramo-Figueroa, V. H., Cardenas, B., Gutierrez-Avedoy, V., and Molina, M. J.: Air quality in North America's most populous city – overview of the MCMA-2003 campaign, Atmos. Chem. Phys, 7, 2447–2473, 2007. Molina, L. T. and Molina, M. J.: Cleaning the air: a comparative study, in: Air Quality in the Mexico Megacity. An integrated assessment, edited by: Molina, L. T. and Molina, M. J., Kluwer Academic Publishers, Netherlands, 2002. Nickerson, C. E., Sosa, G., Hochstein, H., McCaslin, P., Luke, W., and Schanot, A.: Measurements of Mexico City air pollution by a research aircraft, Atmos. Environ., 26B, 445–451, 1992. Parrish, D. D. and Fehsenfeld, F. C.: Methods for gas-phase measurements of ozone, ozone precursors and aerosol precursors, Atmos. Environ., 34, 1921–1957, 2000. Pérez-Vidal, H. and Raga, G. B.: On vertical distribution of pollutants in Mexico City, Atmosfera, 11, 95–108, 1998 Pisano, J. T., Mckendry, I., Steyn, D. G., and Hastie, D. R.: Vertical nitrogen dioxide and ozone concentrations measured from a tethered balloon in the lower Fraser Valley, Atmos. Environ., 31, 2071–2078, 1997. Schifter, I., Diaz, L., Lopez-Salina, E., Rodriguez, R., Avalos, S., and Guerrero, V.: An evaluation of the LPG vehicles program in the Metroploitan Area of Mexico City, J. Air Waste Manage. Assoc., 50, 301–309, 2000. Shirley, T. R., Brune, W. H., Ren, X., Mao, J., Cardenas, B., Volkamer, R., Molina, L. T., Molina, M. J., Lamb, B., Velasco, E., Jobson, T., and Alexander, M.: Atmospheric oxidation in the Mexico City Metropolitan Area (MCMA) during April 2003, Atmos. Chem. Phys. 6, 2753–2765, 2006. Streit, G. E. and Guzmán, F.: Mexico City air quality: Progress of an international collaborative project to define air quality management options, Atmos. Environ., 30, 723–733, 1996. Stull, R. B.: An Introduction to Boundary Layer Meteorology, Kluwer Academic Publishers, Netherlands, 1988. USEPA: Compendium method TO-14a. Determination of volatile organic compounds (VOCs) in ambient air using specially prepared canisters with subsequent analysis by gas chromatography (EPA/625/R-96/010b). Compendium of methods for the determination of toxic organic compounds in ambient air, 2nd Edition, US EPA, Cincinnati, OH, 1999. 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. Velasco, E., Pressley, S., Allwine, E., Westberg, H., and Lamb, B.: Measurements of CO₂ fluxes from the Mexico City urban landscape. Atmos. Environ. 39, 7433-7446, 2005. Velasco, E., Lamb, B., Westeberg, H., Allwine, E., Sosa, G., Arriaga-Colina, J. L., Jonson, 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. Whiteman, C. D., Zhong, S., Bian, X., Fast, J. D., and Doran, J. C.: Boundary layer evolution and regional-scale diurnal circulations over the Mexico Basin and Mexican plateau, J. of Geophys. Res., 105, 10 081–10 102, 2000. Wöhrnschimmel, H., Márquez, C., Mugica, V., Stahel, W. A., Staehelin, J., Cárdenas, B., and Blanco, S.: Vertical profiles and receptor modeling of volatile organic compounds over Southeastern Mexico City, Atmos. Environ, 40, 5125–5136, 2006.