HR: 0800h
AN: A11A-0008    [Abstracts]
TI: Measurements of Trace Gas Fluxes from the Mexico City Urban Landscape
AU: * Lamb, B
EM: blamb@wsu.edu
AF: Washngton State University, Laboratory for Atmospheric Research, Pullman, WA 99164 United States
AU: Velasco, E
AF: Washngton State University, Laboratory for Atmospheric Research, Pullman, WA 99164 United States
AU: Allwine, E
AF: Washngton State University, Laboratory for Atmospheric Research, Pullman, WA 99164 United States
AU: Pressley, S
AF: Washngton State University, Laboratory for Atmospheric Research, Pullman, WA 99164 United States
AU: Westberg, H
AF: Washngton State University, Laboratory for Atmospheric Research, 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: Prazeller, P
AF: Pacific Northwest National Laboratory, P.O.Box 999, MSIN K9-30, Richland, WA 99352 United States
AB: As part of the MCMA 2003 field campaign, we demonstrated the feasibility of using eddy covariance techniques coupled with fast-response sensors to measure urban CO2 and VOC fluxes from a neighborhood of Mexico City, where the spatial variability of surface cover and roughness is high. Eddy covariance methods were used to measure CO2 and organic olefin fluxes where an open path infrared CO2 sensor was used for CO2 measurements and a Fast Olefin Sensor (FOS) was employed for the olefin fluxes. Concentrations of methanol, acetone, toluene and C2-benzenes were measured with a Proton Transfer Reaction Mass Spectrometer (PTR-MS), and fluxes were obtained using a disjunct eddy covariance technique. Stationarity, spectral and co-spectral analyses of the data demonstrated that the underlying requirements for micrometeorological flux measurements were satisfied. The CO2 flux measurements showed that the urban landscape is a net source for CO2 with the highest emissions during the morning (up to 1.60 mg m-2 s-1), and lower emissions during nighttime. The mean daily flux was 0.41 mg m-2 s-1, which is similar to observations in US or European developed cities. The VOC flux results showed that fluxes exhibit a clear diurnal pattern with a strong relationship to vehicular traffic. These data can be used to help assess the accuracy of gridded emission inventories developed for photochemical air quality modeling in Mexico City.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0317 Chemical kinetic and photochemical properties
DE: 0345 Pollution--urban and regional (0305)
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting