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| Titel |
Trace gas and particle emissions from domestic and industrial biofuel use and garbage burning in central Mexico |
| VerfasserIn |
T. J. Christian, R. J. Yokelson, B. Cárdenas, L. T. Molina, G. Engling, S.-C. Hsu |
| 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 ; 10, no. 2 ; Nr. 10, no. 2 (2010-01-21), S.565-584 |
| Datensatznummer |
250007962
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| Publikation (Nr.) |
 copernicus.org/acp-10-565-2010.pdf |
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| Zusammenfassung |
| In central Mexico during the spring of 2007 we measured
the initial emissions of 12 gases and the aerosol speciation for elemental
and organic carbon (EC, OC), anhydrosugars, Cl−, NO3−, and 20
metals from 10 cooking fires, four garbage fires, three brick making kilns,
three charcoal making kilns, and two crop residue fires. Global biofuel use
has been estimated at over 2600 Tg/y. With several simple case studies we
show that cooking fires can be a major, or the major, source of several
gases and fine particles in developing countries. Insulated cook stoves with
chimneys were earlier shown to reduce indoor air pollution and the fuel use
per cooking task. We confirm that they also reduce the emissions of VOC
pollutants per mass of fuel burned by about half. We did not detect HCN
emissions from cooking fires in Mexico or Africa. Thus, if regional source
attribution is based on HCN emissions typical for other types of biomass
burning (BB), then biofuel use and total BB will be underestimated in much
of the developing world. This is also significant because cooking fires are
not detected from space. We estimate that ~2000 Tg/y of garbage are
generated globally and about half may be burned, making this a commonly
overlooked major global source of emissions. We estimate a fine particle
emission factor (EFPM2.5) for garbage burning of
~10.5±8.8 g/kg, which is in reasonable agreement with very limited previous work. We
observe large HCl emission factors in the range 2–10 g/kg. Consideration of
the Cl content of the global waste stream suggests that garbage burning may
generate as much as 6–9 Tg/yr of HCl, which would make it a major source of
this compound. HCl generated by garbage burning in dry environments may have
a relatively greater atmospheric impact than HCl generated in humid areas.
Garbage burning PM2.5 was found to contain levoglucosan and K in
concentrations similar to those for biomass burning, so it could be a source
of interference in some areas when using these tracers to estimate BB.
Galactosan was the anhydrosugar most closely correlated with BB in this
study. Fine particle antimony (Sb) shows initial promise as a garbage
burning tracer and suggests that this source could contribute a significant
amount of the PM2.5 in the Mexico City metropolitan area. The fuel
consumption and emissions due to industrial biofuel use are difficult to
characterize regionally. This is partly because of the diverse range of
fuels used and the very small profit margins of typical micro-enterprises.
Brick making kilns produced low total EFPM2.5 (~1.6 g/kg), but
very high EC/OC ratios (6.72). Previous literature on brick kilns is scarce
but does document some severe local impacts. Coupling data from Mexico,
Brazil, and Zambia, we find that charcoal making kilns can exhibit an 8-fold
increase in VOC/CO over their approximately one-week lifetime. Acetic acid
emission factors for charcoal kilns were much higher in Mexico than
elsewhere. Our dirt charcoal kiln EFPM2.5 emission factor was
~1.1 g/kg, which is lower than previous recommendations intended for all
types of kilns. We speculate that some PM2.5 is scavenged in the walls of dirt kilns. |
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