Identification of markers for chemical mass balance receptor model

In a Chemical Mass Balance (CMB) analysis, a limited number of marker elements have been considered to be critical to estimate the contributions of specific sources. These markers include such elements as vanadium (V) for oil-fired power plants, zinc (Zn) for municipal refuse incinerators, etc. A marker element in a source profile is typically characterized by its high abundance relative to the other elements. These elements tend to be identified as data points of 'potential influence'. However, it is important to note that such a chemical element may not have an 'actual' influence to the CMB source estimates. In this study, some marker elements chosen in the previous studies of the Washington, D.C. area sources were found to be likely to have 'potential influences' but did not exhibit actual impact on the source estimates. The methodologies applied in this article provide an understanding of the relationship between markers and sources in CMB linear receptor models for urban scale apportionment and possibly can be extended to a regional scale. The CMB modelers can include sources according to those that have been identified through a field survey or an emission inventory, and the statistics permit the association of the natural markers, if there is any, to these sources.