A combined TTFA/CMB receptor modeling approach and its application to air pollution sources in China

Abstract

Abstract The possibility of using a two step method of identifying and quantifying air pollution emissions in an urban environment was examined in this paper. The procedure uses a numerical model called Target Transformation Factor Analysis (TTFA) to estimate source emission profiles using ambient trace element air concentration data. The profiles estimated by TTFA are then employed in a Chemical Mass Balance (CMB) source apportionment analysis for an air shed. Other known sources are estimated using source signatures from the literature. The results show that TTFA can be used to provide quantitative estimates of air pollution source profiles for an urban center in China. The number of profiles for unique source types was limited for this data set since emissions from certain types of sources co-varied during each sampling day. Consequently, the CMB analyses that applied the TTFA source profiles needed to be supplemented with standard U.S. EPA source profiles. TTFA can identify source categories of airborne pollution for specific locations, as well as give quantitative data on the composition of the emissions from those source types. The source profiles obtained through a TTFA can be used in a chemical mass balance source apportionment calculation. Including source profiles estimated by TTFA in a chemical mass balance analysis provides a comprehensive source apportionment methodology which can help researchers more accurately characterize the air pollution source types that pose the greatest concern to human health.