Eddy covariance flux measurements of pollutant gases in urban Mexico City
Eddy covariance (EC) flux measurements of the atmosphere/surface exchange of gases over an urban area are a direct way to improve and evaluate emissions inventories, and, in turn, to better understand urban atmospheric chemistry and the role that cities play in regional and global chemical cycles. A...
| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2009-10-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/9/7325/2009/acp-9-7325-2009.pdf |
| _version_ | 1818317590352625664 |
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| author | E. Velasco S. Pressley R. Grivicke E. Allwine T. Coons W. Foster B. T. Jobson H. Westberg R. Ramos F. Hernández L. T. Molina B. Lamb |
| author_facet | E. Velasco S. Pressley R. Grivicke E. Allwine T. Coons W. Foster B. T. Jobson H. Westberg R. Ramos F. Hernández L. T. Molina B. Lamb |
| author_sort | E. Velasco |
| collection | DOAJ |
| description | Eddy covariance (EC) flux measurements of the atmosphere/surface exchange of
gases over an urban area are a direct way to improve and evaluate emissions
inventories, and, in turn, to better understand urban atmospheric chemistry
and the role that cities play in regional and global chemical cycles. As
part of the MCMA-2003 study, we demonstrated the feasibility of using eddy
covariance techniques to measure fluxes of selected volatile organic
compounds (VOCs) and CO<sub>2</sub> from a residential district of Mexico City
(Velasco et al., 2005a, b). During the MILAGRO/MCMA-2006 field campaign, a
second flux measurement study was conducted in a different district of
Mexico City to corroborate the 2003 flux measurements, to expand the number
of species measured, and to obtain additional data for evaluation of the
local emissions inventory. Fluxes of CO<sub>2</sub> and olefins were measured by
the conventional EC technique using an open path CO<sub>2</sub> sensor and a Fast
Isoprene Sensor calibrated with a propylene standard. In addition, fluxes of
toluene, benzene, methanol and C<sub>2</sub>-benzenes were measured using a
virtual disjunct EC method with a Proton Transfer Reaction Mass
Spectrometer. The flux measurements were analyzed in terms of diurnal
patterns and vehicular activity and were compared with the most recent
gridded local emissions inventory. In both studies, the results showed that
the urban surface of Mexico City is a net source of CO<sub>2</sub> and VOCs with
significant contributions from vehicular traffic. Evaporative emissions from
commercial and other anthropogenic activities were significant sources of
toluene and methanol. The results show that the emissions inventory is in
reasonable agreement with measured olefin and CO<sub>2</sub> fluxes, while
C<sub>2</sub>-benzenes and toluene emissions from evaporative sources are
overestimated in the inventory. It appears that methanol emissions from
mobile sources occur, but are not reported in the mobile emissions
inventory. |
| first_indexed | 2024-12-13T09:39:44Z |
| format | Article |
| id | doaj.art-cd6ca01a210d4165ab744c216c26d9d8 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-13T09:39:44Z |
| publishDate | 2009-10-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-cd6ca01a210d4165ab744c216c26d9d82022-12-21T23:52:14ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242009-10-019197325734210.5194/acp-9-7325-2009Eddy covariance flux measurements of pollutant gases in urban Mexico CityE. Velasco0S. Pressley1R. Grivicke2E. Allwine3T. Coons4W. Foster5B. T. Jobson6H. Westberg7R. Ramos8F. Hernández9L. T. Molina10B. Lamb11Molina Center for Energy and the Environment (MCE2), La Jolla, CA, USALaboratory for Atmospheric Research, Dept. of Civil and Environmental Engineering, Washington State University, Pullman, WA, USALaboratory for Atmospheric Research, Dept. of Civil and Environmental Engineering, Washington State University, Pullman, WA, USALaboratory for Atmospheric Research, Dept. of Civil and Environmental Engineering, Washington State University, Pullman, WA, USALaboratory for Atmospheric Research, Dept. of Civil and Environmental Engineering, Washington State University, Pullman, WA, USALaboratory for Atmospheric Research, Dept. of Civil and Environmental Engineering, Washington State University, Pullman, WA, USALaboratory for Atmospheric Research, Dept. of Civil and Environmental Engineering, Washington State University, Pullman, WA, USALaboratory for Atmospheric Research, Dept. of Civil and Environmental Engineering, Washington State University, Pullman, WA, USASecretaría del Medio Ambiente del Gobierno del Distrito Federal, México D.F., MéxicoSecretaría del Medio Ambiente del Gobierno del Distrito Federal, México D.F., MéxicoMolina Center for Energy and the Environment (MCE2), La Jolla, CA, USALaboratory for Atmospheric Research, Dept. of Civil and Environmental Engineering, Washington State University, Pullman, WA, USAEddy covariance (EC) flux measurements of the atmosphere/surface exchange of gases over an urban area are a direct way to improve and evaluate emissions inventories, and, in turn, to better understand urban atmospheric chemistry and the role that cities play in regional and global chemical cycles. As part of the MCMA-2003 study, we demonstrated the feasibility of using eddy covariance techniques to measure fluxes of selected volatile organic compounds (VOCs) and CO<sub>2</sub> from a residential district of Mexico City (Velasco et al., 2005a, b). During the MILAGRO/MCMA-2006 field campaign, a second flux measurement study was conducted in a different district of Mexico City to corroborate the 2003 flux measurements, to expand the number of species measured, and to obtain additional data for evaluation of the local emissions inventory. Fluxes of CO<sub>2</sub> and olefins were measured by the conventional EC technique using an open path CO<sub>2</sub> sensor and a Fast Isoprene Sensor calibrated with a propylene standard. In addition, fluxes of toluene, benzene, methanol and C<sub>2</sub>-benzenes were measured using a virtual disjunct EC method with a Proton Transfer Reaction Mass Spectrometer. The flux measurements were analyzed in terms of diurnal patterns and vehicular activity and were compared with the most recent gridded local emissions inventory. In both studies, the results showed that the urban surface of Mexico City is a net source of CO<sub>2</sub> and VOCs with significant contributions from vehicular traffic. Evaporative emissions from commercial and other anthropogenic activities were significant sources of toluene and methanol. The results show that the emissions inventory is in reasonable agreement with measured olefin and CO<sub>2</sub> fluxes, while C<sub>2</sub>-benzenes and toluene emissions from evaporative sources are overestimated in the inventory. It appears that methanol emissions from mobile sources occur, but are not reported in the mobile emissions inventory.http://www.atmos-chem-phys.net/9/7325/2009/acp-9-7325-2009.pdf |
| spellingShingle | E. Velasco S. Pressley R. Grivicke E. Allwine T. Coons W. Foster B. T. Jobson H. Westberg R. Ramos F. Hernández L. T. Molina B. Lamb Eddy covariance flux measurements of pollutant gases in urban Mexico City Atmospheric Chemistry and Physics |
| title | Eddy covariance flux measurements of pollutant gases in urban Mexico City |
| title_full | Eddy covariance flux measurements of pollutant gases in urban Mexico City |
| title_fullStr | Eddy covariance flux measurements of pollutant gases in urban Mexico City |
| title_full_unstemmed | Eddy covariance flux measurements of pollutant gases in urban Mexico City |
| title_short | Eddy covariance flux measurements of pollutant gases in urban Mexico City |
| title_sort | eddy covariance flux measurements of pollutant gases in urban mexico city |
| url | http://www.atmos-chem-phys.net/9/7325/2009/acp-9-7325-2009.pdf |
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