Lignin pyrolysis products, lignans, and resin acids as specific tracers of plant classes in emissions from biomass combustion

Biomass smoke aerosols contain thermally unaltered and partially altered biomarker compounds from major vegetation taxa. These compounds range from C₈ to C_ (31) and include phytosterols, lignans, phenolic products from lignin, and diterpenoids from resins. Certain of the higher molecular weight biomarkers are vaporized from the parent plant material and subsequently condense unaltered into the particle phase. Other compounds undergo pyrolytic alteration and possibly dimerization. In both cases it is possible to assign many of these compounds to the plant taxa of the unburned fuel. The diterpenoids are good indicators for smoke from burning of gymnosperm wood. The relative distribution of the OH/OCH₃ substituent patterns on the phenolic products indicates the plant class of the biomass that was burned. Application of these relationships to the interpretation of ambient smoke aerosols may permit further evaluation of the sources that contribute to regional biomass burning.