Biomass burning organic aerosol in Europe and Asia: Molecular composition and impact on air quality
Final Report Abstract
Biomass burning emits large amounts of organic aerosol particles into the atmosphere. Important sources are the burning of wood for house heating in Europe and the field burning of agricultural waste during the harvesting season in Asia. These emissions have a strong impact on air quality and can have adverse effects on human health. Besides primary particles which are directly emitted by the fire, the formation of secondary organic aerosols from volatile organic gases plays an important role during transport and chemical aging of smoke plumes. Most of these chemical transformations, as well as the detailed chemical composition of primary and secondary emissions from biomass burning are not well understood at present. In this project, biomass burning emissions and their atmospheric processing were studied both in a smog chamber and in the real atmosphere. In the chamber experiments, a large number of organic compounds was measured in the primary smoke particle samples, including many aliphatic and aromatic phenolic compounds. There concentrations were compared before and after chemical ageing of the plume and many of them were found to increase, due to continuous oxidation of gaseous precursors in the plume. Other compounds were found do decrease in concentration due to oxidation and chemical transformation in the particle phase. These changes in chemical composition upon ageing of the plume in the atmosphere can be used for a refined source apportionment of ambient organic particle mass. In rural samples impacted by residential heating with wood, contributions of fresh and aged biomass burning could be determined from their detailed chemical fingerprints. The data obtained in this project has helped to improve the understanding of emissions, transformations, and impacts of biomass burning in different atmospheric regimes.
