A COMBINED TTFA CMB RECEPTOR MODELING APPROACH AND ITS APPLICATION TOAIR-POLLUTION SOURCES IN CHINA

The possibility of using a two step method of identifying and quantify ing air pollution emissions in an urban environment was examined in th is paper. The procedure uses a numerical model called Target Transform ation Factor Analysis (TTFA) to estimate source emission profiles usin g ambient trace element air concentration data. The profiles estimated by TTFA are then employed in a Chemical Mass Balance (CMB) source app ortionment analysis for an air shed. Other known sources are estimated using source signatures from the literature. The results show that TT FA can be used to provide quantitative estimates of air pollution sour ce profiles for an urban center in China. The number of profiles for u nique source types was limited for this data set since emissions from certain types of sources co-varied during each sampling day, Consequen tly, the CMB analyses that applied the TTFA source profiles needed to be supplemented with standard U.S. EPA source profiles. TTFA can ident ify source categories of airborne pollution for specific locations, as well as give quantitative data on the composition of the emissions fr om 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 wh ich can help researchers more accurately characterize the air pollutio n source types that pose the greatest concern to human health.