Trace gas and particle emissions from domestic and industrial biofuel use and garbage burning in central Mexico

Abstract

Abstract. 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. 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 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 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 thin 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, probably due to the use of tannin-rich oak fuel. 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.

Chlorine activation indoors and outdoors via surface-mediated reactions of nitrogen oxides with hydrogen chloride

“…Direct emissions include garbage burning (7), incineration of municipal and medical wastes, burning of biomass, agricultural products and coal, and industrial processes, e.g., semiconductor and petroleum manufacturing (5). Natural sources in air include volcanic eruptions and reactions of sea salt and organochlorine compounds (5).…”

Evaluating simulated primary anthropogenic and biomass burning organic aerosols during MILAGRO: implications for assessing treatments of secondary organic aerosols

“…But the subsequent decrease in simulated POA reversed at 17:00 UTC (11:00 LT) instead of continuing to decrease for four more hours during the afternoon. As discussed previously with CO and EC, there are likely uncertainties in the local emissions that may contribute to errors on POA at this site, including brick kilns (Christian et al, 2009) and other local sources.…”

“…Recently Christian et al (2009) suggested that trash burning at municipal landfills could be responsible for about 29% of the PM 2.5 present in the urban Mexico City area. However, their estimate has a high uncertainty, since it is based on extrapolating measurements from four short-term trash burning events and the use of antimony (chemical symbol Sb) as a tracer for trash burning.…”

Observing and understanding the Southeast Asian aerosol system by remote sensing: An initial review and analysis for the Seven Southeast Asian Studies (7SEAS) program

“…In addition, numerous small-scale enterprises such as brick kilns burn a variety of fuels including garbage, crop waste, tires, used motor oil, scrap wood, sawdust, and charcoal (Le and Oanh, 2010). Although an inventory of these fuel-intensive enterprises has not been performed in SEA, such informal operations account for up to 50% of non-agricultural employment in some similar economic areas over the globe (Christian et al, 2010).…”