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- Hedberg Larsson, Emma, 1976-
(författare)
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Source-Receptor Modeling of Air Pollution : Assessment of Source Contributions: Source Characterization and Chemometric Applications
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Particles released to the atmosphere from anthropogenic sources affect the Earth’s climate as well as the health of the population. Anthropogenic sources of atmospheric particles are e.g. the combustion of biomass and fossil fuels, road, brake and tire wear and various industrial activities. There is great interest to find the importance of different sources to the particle concentrations in the atmosphere to minimize their impact on climate and health. This work investigates how well particle sources are assessed when using source-receptor models. The main focus of this work lies in retrieving the uncertainties and difficulties of using these models on sampled particulate data. Comparison is made with other methods, e.g. a meteorological air pollution dispersion model and a tracer method.Depending on the source origin, the uncertainties of the source profiles are different and require different approaches to be quantified. Conclusions drawn from this thesis are:• assessment of point-sources which affect the sampling site less frequently, requires longer periods of sampling. • at a sampling site impacted by many different sources the time resolution of the samples has to be high in order to enable a differentiation between the sources. • natural sources, or area sources that impact the sampling site frequently, requires fewer samples and can be assessed even when the time resolution of the samples is as low as 3-4 days. This is further stressed by the fact that the natural sources are well characterized in terms of inorganic compounds.Using levoglucosan as sole quantitative tracer for domestic wood burning was shown to be associated with large uncertainties. In contrast to the unique tracer method for source assessment, the multivariate methods will also point at uncertainties in the data model, when the model cannot give a good estimate from the sampled data.
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- Krecl, Patricia, et al.
(författare)
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Contribution of residential wood combustion to hourly winter aerosol in Northern Sweden determined by positive matrix factorization
- 2008
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Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 8:13, s. 3639-3653
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Tidskriftsartikel (refereegranskat)abstract
- The combined effect of residential wood combustion (RWC) emissions with stable atmospheric conditions. which frequently occurs in Northern Sweden during wintertime, can deteriorate the air quality even in small towns. To estimate the contribution of RWC to the total atmospheric aerosol loading, positive matrix factorization (PMF) was applied to hourly mean particle number size distributions measured in a residential area in Lycksele during winter 2005/2006. The sources were identified based on the particle number size distribution profiles of the PMF factors., the diurnal contributions patterns estimated by PMF for both weekends and weekdays, and correlation of the modeled particle number concentration per factor with measured aerosol mass concentrations (PM10, PM1, and light-absorbing carbon M-LAC). Through these analyses. the factors were identified as local traffic (factor 1), local RWC (factor 2), and local RWC plus Ion-range transport (LRT) of aerosols (factor 3). In some occasions, the PMF model could not separate the contributions of local RWC from background concentrations since their particle number size distributions partially overlapped. As a consequence, we report the contribution of RWC as a range of values, being the minimum determined by factor 2 and the possible maximum as the contributions of both factors 2 and 3. A multiple linear regression (MLR) of observed PM10, PM1, total particle number, and M-LAC concentrations is carried out to determine the source contribution to these aerosol variables. The results reveal RWC is an important source of atmospheric particles in the size range 25-606 nm (44-57%), PM10 (36-82%), PM1 (31-83%), and M-LAC (40-76%) mass concentrations in the winter season.
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