Trace gas emissions from tropical biomass fires: Yucatan Peninsula,Mexico

Mixing ratios for carbon dioxide (CO₂), carbon monoxide (CO), hydrogen (H₂), methane (CH₄) and total non-methane hydrocarbons (TNMHC) were determined from the smoke plumes of two small (～0.25 ha) prescribed biomass fires conducted on the Yucatan Peninsula in Mexico. In the region of these fires the combination of climate and shallow soils produces a scrubby and stunted forest with species composition similar to the Brazilian rain forest, but at a noticeably reduced size. Aircraft collections of smoke from these fires were analysed and used to determine CO₂-normalized emission ratios (ΔX/ΔCO₂; v/v; where Δ = in-plume specie concentration less background concentration) for CO, H₂, CH₄ and TNMHC produced and released into the atmosphere from these fires. Suprisingly, high mean emission ratios for TNMHCs (～1.7% of CO₂ release) and H₂ (～2.5% of CO₂) were determined. Emission ratios for CO (～7%) and CH₄ (～0.7%), however, were found to fall within expected bounds.