Composition and Size Distribution of Residential Wood Smoke Particles

Residential wood combustion emissions are an important source of organic and elemental carbon particulate matter in many urban and suburban areas. This research determined the organic and elemental carbon composition and size distribution of particulate emissions for hot- and cool-burning wood stoves and from conventional fireplaces. Sampling was done from smoke plumes which had been cooled and diluted by ambient air so that the particulate composition measured would be representative of smoke particles as they actually exist in the atmosphere. Organic and elemental carbon were determined by thermo-optical carbon analysis. Corrections were made for vapor organic carbon adsorption on quartz fiber filters during sampling. Particles emitted by hot-burning stoves were black, had a unimodal size distribution, and contained from 20% to 60% carbon (primarily elemental carbon) and high levels of trace elements (11% K, 1% S, 3% Cl). In contrast, particles from cool-burning stoves were tan, had a bimodal size distribution, and contained from 55% to 60% carbon (almost entirely organic carbon) and minute amounts (< 0.1%) of trace elements. The composition of particles emitted by fireplaces had compositions that were intermediate between those of hot- and cool-burning stoves, but tended to be more similar to cool burning stove emissions.