Abstract:
This study provides an estimate for the proportion of atmospheric fine particulate matter attributable to the combustion of wood. The 1997 addition of a fine (measuring less than 2.5 microns in aerodynamic diameter) particulate matter standard to the National Ambient Air Quality Standard requires determination of the sources of this particulate matter for the guidance of regulatory strategies. Interpretation of ambient air quality data collected in Seattle, using various source apportionment models vary significantly in the proportionate mass fraction of PM2.5 assigned to diesel versus wood smoke source categories. This discrepancy can have a significant impact on risk assessments, epidemiologic studies, and control strategies, all of which rely on an accurate assessment of the sources and composition of particulate matter. Incorporation of source-specific chemical tracers for combustion-derived PM2.5 into chemical mass balance and other models for source apportionment has been used to strengthen the power of these models to discriminate among combustion source categories. In this study, the use of levoglucosan, a polar organic compound produced by biomass combustion, as such a tracer is evaluated.