Retene—a molecular marker of wood combustion in ambient air

Abstract

The use of wood as a fuel has increased since the oil embargo in 1973. Several studies have shown that wood combustion may make a significant contribution to air pollution. Using ¹⁴C as a tracer for contemporary carbonaceous materials, 30–70% of the atmospheric carbon has been shown to originate from wood combustion in areas affected by this source^1–3. Other studies have shown that emissions from wood combustion contain large amounts of particles^4–6 and organic compounds, one class being poly cyclic aromatic hydrocarbons (PAH)^7–11. However, these compounds are also formed by combustion of other carbonaceous materials. In our studies on PAH in wood combustion emissions and in ambient air in wood-heated residential areas, we have identified several PAH compounds which may be related to combustion of coniferous wood. These are alkylated phenanthrene compounds with the main compound 1-methyl-7-isopropylphenanthrene (trivial name retene) formed by thermal degradation of resin compounds in the wood.