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| Titel |
Emissions from forest fires near Mexico City |
| VerfasserIn |
R. J. Yokelson, S. P. Urbanski, E. L. Atlas, D. W. Toohey, E. C. Alvarado, J. D. Crounse, P. O. Wennberg, M. E. Fisher, C. E. Wold, T. L. Campos, K. Adachi, P. R. Buseck, W. M. Hao |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 7, no. 21 ; Nr. 7, no. 21 (2007-11-09), S.5569-5584 |
| Datensatznummer |
250005246
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| Publikation (Nr.) |
 copernicus.org/acp-7-5569-2007.pdf |
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| Zusammenfassung |
| The emissions of NOx (defined as NO (nitric oxide) +
NO2 (nitrogen dioxide)) and hydrogen cyanide (HCN), per unit amount of
fuel burned, from fires in the pine forests that dominate the mountains
surrounding Mexico City (MC) are about 2 times higher than normally observed
for forest burning. The ammonia (NH3) emissions are about average for
forest burning. The upper limit for the mass ratio of NOx to volatile
organic compounds (VOC) for these MC-area mountain fires was ~0.38,
which is similar to the NOx/VOC ratio in the MC urban area emissions
inventory of 0.34, but much larger than the NOx/VOC ratio for tropical
forest fires in Brazil (~0.068). The nitrogen enrichment in the fire
emissions may be due to deposition of nitrogen-containing pollutants in the
outflow from the MC urban area. This effect may occur worldwide wherever
biomass burning coexists with large urban areas (e.g. the tropics,
southeastern US, Los Angeles Basin). The molar emission ratio of HCN to
carbon monoxide (CO) for the mountain fires was 0.012±0.007, which is
2–9 times higher than widely used literature values for biomass burning. The
ambient molar ratio HCN/CO in the MC-area outflow is about 0.003±0.0003.
Thus, if only mountain fires emit significant amounts of HCN, these
fires may be contributing about 25% of the CO production in the MC-area
(~98–100 W and 19–20 N). Comparing the PM10/CO and PM2.5/CO mass
ratios in the MC Metropolitan Area emission inventory (0.0115 and 0.0037) to
the PM1/CO mass ratio for the mountain fires (0.133) then suggests that
these fires could produce as much as ~79–92% of the primary fine
particle mass generated in the MC-area. Considering both the uncertainty in
the HCN/CO ratios and secondary aerosol formation in the urban and fire
emissions implies that about 50±30% of the "aged" fine particle
mass in the March 2006 MC-area outflow could be from these fires. |
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