Building the future by doing more together

BIOEMI: Contribution of biomass combustion to air pollutant emissions
Coordinator - Célia Alves
Programme - PTDC/AMB/65706/2006
Execution dates - 2007-11-01 - 2011-10-31 (48 Months)
Funding Entity - FCT
Funding for CESAM - 125618 €
Total Funding - 199958 €
Proponent Institution - Universidade de Aveiro
Participating Institutions
Universidade de Aveiro
Instituto Tecnológico e Nuclear

see also http://www.cesam.ua.pt/bioemi


Aerosols are minute particles suspended in the atmosphere. The major aerosol components include inorganic substances such as sulphates and carbonaceous species, which are divided into organic carbon (OC) and elemental carbon (EC). Atmospheric aerosol particles have a profound effect on climate. The direct and indirect radiative forcing of climate by anthropogenic aerosols is believed to be similar in magnitude but opposite in sign to the global warming caused by the emissions of greenhouse gases. Fine particles and the associated organic compounds are also of current concern because of their putative health effects. On a global basis the major source of carbonaceous aerosols is due to biomass burning. In Europe, this emission source could contribute up to 80% of the atmospheric aerosol mass, as a recent research project has pointed out. In Portugal, it was estimated that around 390000 ton/year of wood is burned in fireplaces. Additionally, in the last decade, fires have destroyed around 110000 ha/year of forest, what corresponds to an annual loss of biomass of approximately 400000 ton. These combustions result in high levels of toxic air pollutants (radionuclides, dioxins, PAH, etc.) and a large perturbation to atmospheric chemistry. Accurate quantification of the amounts of trace gases and particulate matter emitted from forest fires and other sources of biomass burning on a regional and global basis is required by a number of users, including scientists studying a wide range of atmospheric processes, national governments who are required to report greenhouse gas emissions, and those interested quantifying the sources of air pollution that affect human health at regional scales. In Europe, data on detailed emission factors from biomass burning are rather inexistent. Emission inventories and source apportionment, photochemistry and climate change models use default values obtained for US biofuels, uncommon in Europe. Thus, it is desirable to use more specific locally available data. The objective of this study is to quantify the contribution of biomass combustion sources to atmospheric trace gases and fine particle concentrations throughout most of Portugal. Both the spatial and seasonal variation of biomass smoke concentrations will be determined. A series of field experiments involving source sampling, laboratory organic chemical analysis of source and atmospheric samples combined with air quality model development is proposed. First, those biomass combustion source types that account for approximately 90% of biomass smoke generation will be estimated via construction of a national emission inventory based on existing source data. Then a source test program will be undertaken in which a dilution source sampling system will be used to measure the fine particle mass and trace gases emission rates, particle elemental composition and particulate organic speciation. In order for organic chemical tracer techniques to be applied to communities across Portugal, differences in wood smoke composition that arise from differences in the type of wood burned in various regions must be understood. A continental-scale accounting of traces gases, particulate organic and inorganic compound emissions from different source types will be performed to quantify the regional differences in wood smoke composition that exist between different parts of Portugal and those published for other regions of the world. Sources types to be tested include the obvious major contributors (fireplace combustion of wood, wood stoves, prescribed burns and forest fires). Organic chemical fingerprints specific to the most important combinations of combustor type and fuel type will be determined by GC-MS analysis of the source samples. The emission rates of important wood smoke markers (e.g. cellulose, thermally altered resin acids, syringol and guaiacyl-type compounds, levoglucosan, plant waxes, radionuclides, etc.), which vary greatly with wood and combustions types, will be determined. By weighting the source test results in proportion to the availability of firewood from specific tree species, the quantities of wood burned for domestic purposes in each locale, the area burned by forest fires and forest types, it will be possible to produce global emission estimates. Then some apportionment models can be applied that employ those chemical tracers to calculate, based on the source signatures, the contribution of biomass smoke to atmospheric fine particle mass concentrations already measured during previous research projects.




Members on this project
Casimiro Pio
researcher
Cátia Gonçalves
PhD student
Célia A. Alves
coordinator
Luís Tarelho
Researcher

researcher
Teresa Nunes
researcher

CESAM Funding: