Stable isotopic compositions of carbon monoxide from biomass burning experiments

The stable isotope composition of carbon monoxide (CO) from burning plants was measured to provide insight about isotopic compositions of CO from biomass burning. Both 13C/12C and 18O/16O ratios of CO decreased with the time from ignition and those trends were not depending on the plant species. δ13C values of produced CO were heavier (0.6–3.6‰ V-PDB) than those of the burned plants during flaming stage, but they became lighter (−2.1–−6.8‰ V-PDB) during smoldering stage. Because CO production is enhanced in smoldering stage, average isotopic compositions of CO from biomass burning would be lighter than those of burned plants. For atmospheric model calculations on CO isotopes, isotopic fractionation of CO from biomass burning should be considered