HR: 14:55h
AN: A13E-02 INVITED     [Abstracts]
TI: Mexico City's active photochemistry: conclusions from the MCMA-2003 study
AU: * Brune, W
EM: brune@ems.psu.edu
AF: Pennsylvania State University, Department of Meteorology, 503 Walker Building, University Park, PA 16802 United States
AU: Shirley, T
AF: Pennsylvania State University, Department of Meteorology, 503 Walker Building, University Park, PA 16802 United States
AU: Lesher, R
AF: Pennsylvania State University, Department of Meteorology, 503 Walker Building, University Park, PA 16802 United States
AU: Mao, J
AF: Pennsylvania State University, Department of Meteorology, 503 Walker Building, University Park, PA 16802 United States
AU: Volkamer, R
AF: Maasachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Scineces, 77 Massachusetts Av., Cambidge, MA 02139 United States
AU: Molina, L
AF: Maasachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Scineces, 77 Massachusetts Av., Cambidge, MA 02139 United States
AU: Molina, M
AF: Maasachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Scineces, 77 Massachusetts Av., Cambidge, MA 02139 United States
AU: Velasco, E
AF: Washington State University, Civil and Environmental Engineering, Sloan Hall 101, Spokane Street, Pullman, WA 99164 United States
AU: Westberg, H
AF: Washington State University, Civil and Environmental Engineering, Sloan Hall 101, Spokane Street, Pullman, WA 99164 United States
AU: Lamb, B
AF: Washington State University, Civil and Environmental Engineering, Sloan Hall 101, Spokane Street, Pullman, WA 99164 United States
AU: Jobson, T
AF: Pacific Northwest National Laboratory, P.O. Box 999, MSIN K9-30, Richland, WA 99352 United States
AU: Alexander, M
AF: Pacific Northwest National Laboratory, P.O. Box 999, MSIN K9-30, Richland, WA 99352 United States
AU: Gonzalez, B C
AF: General Direction of the National Center for Environmental Research and Training (CENICA) - National Institute of Ecology (INE), Perif‚rico 5000, Col. Insurgentes Cuicuilco, Delegaci¢n Coyoac n, D.F 04530 Mexico
AB: Mexico City Metropolitan Area's active photochemistry was studied using an extensive suite of measurements on the CENICA environmental laboratory's roof, as part of the MCMA-2003 field study. Intense morning sunlight photolyzed HONO and HCHO, producing hydrogen oxides (OH and HO$_2$) at high rates. The HO$_x$ interacted with rush-hour volatile organic compounds (VOCs) and nitrogen oxides (NO$_x$), amplifying the production rate of ozone and nitric acid. With typically 100 ppbv of NO$_x$ and 1 ppmC of VOCs, ozone production rates exceeded 30 ppbv/hour, routinely creating in excess of 150 ppbv of ozone, even though the midday mixed layer was more than 3 km deep. Analyses of glyoxal, a product of VOC oxidation, and the hydroperoxyl radical (HO$_2$) indicate that MCMA's ozone production was VOC-limited during morning rush hour, when typically « of the ozone is produced, and for a significant number of days during midday and afternoon at the site. Aspects of Mexico City's active photochemistry will be compared to the observed photochemistry in U.S. urban areas.
DE: 0322 Constituent sources and sinks
DE: 0345 Pollution--urban and regional (0305)
DE: 0365 Troposphere--composition and chemistry
DE: 0368 Troposphere--constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting