Total ambient particulate concentrations collected on a filter are a mix of concentrations from unknown sources of particulates. It is often necessary to quantify source impacts of measured concentrations on a filter, in a process called source apportionment. The measured particulate concentrations are expressed as a linear sum of products of two unknown variables of source compositions, and source apportionments. In an aerosol source-apportionment study, this bilinear problem is usually solved with a multivariate receptor model. 

iGBu has recently developed the most advanced multivariate source apportionment model, entitled SMP, and applied it to three sets of data: PAHs, PM2.5 and PM10. It was first applied to particulate PAHs data to identify and quantify the regional influence. It was then applied to winter-season Kathmandu Valley PM10 data. This study revealed the four primary particulate carbon sources and quantified their source contributions. It also suggested several useful particulate carbon mitigation methods that could be applied to the Kathmandu Valley region, as well as other areas in South Asia with similar sources and high particulate carbon concentrations. In the third study, the SMP model was applied to the fully speciated PM2.5 data, including 85 organic compounds, which revealed the source compositions and contributions from nine sources. For the first time, two sources (secondary and biomass burning sources) were distinguished between the transported and locally generated source.  

The SMP model has a clear advantage over existing multivariate models due to the implementation of all five known Fundamental Natural Physical Constraints (FNPCs). Thus, the SMP model results are more accurate and therefore more trustworthy than any of the other existing models. Details of the SMP model and its application to PM data can be found here.  

iGBu has a wealth of experience when it comes to aerosol source apportionment. We assist government agencies, independent researchers, and industry clients to design and conduct air or water quality source apportionment studies. This in turn helps them to develop efficient control strategies to attain regulatory and research goals. If you need assistance in source apportionment of air or water quality, please contact us at