A method for smoke marker measurements and its potential application for determining the contribution of biomass burning from wildfires and prescribed fires to ambient PM2.5 organic carbon

Abstract

Biomass burning is an important source of particulate organic carbon (OC) in the atmosphere. Quantifying this contribution in time and space requires a means of routinely apportioning contributions of smoke from biomass burning to OC. Smoke marker (for example, levoglucosan) measurements provide the most common approach for making this determination. A lack of source profiles for wildfires and prescribed fires and the expense and complexity of traditional smoke marker measurement methods have thus far limited routine estimates of these contributions to ambient aerosol concentrations and regional haze. We report here on the collection of source profiles for combustion of numerous wildland fuels and on the development of an inexpensive and robust technique for routine smoke marker measurements. Hi‐Volume filter source samples were collected during two studies at the Fire Science Laboratory in Missoula, MT in 2006 and 2007. Levoglucosan (and other carbohydrates) were measured in these samples using high‐performance anion‐exchange chromatography with pulsed amperometric detection. Results of this analysis along with water‐soluble potassium, OC, and elemental carbon are presented. The results show that emissions of levoglucosan are fairly correlated with OC with an average ratio of 0.031 μ g C/μ g C. Further, there was a definite pattern that emerged based on fuel component burned with the typical levoglucosan/OC ratio of branches > straw > needles > leaves. Additionally, this carbohydrate measurement method appears to provide fingerprint information about the type of fuel burned that could help constrain profiles chosen for aerosol source apportionment and lead to a better determination of source contributions from biomass burning.