Application of receptor modeling methods

The use of atmospheric compositional data for the identification and apportionment of sources has been ongoing for more than 40 years. Beginning in the 1960s, it was recognized that data analysis techniques could be applied to data and resolve combination of constituents that represent sources. In the late 1970s, these data analysis tools came to be called Receptor Models. This paper traces the early history of receptor models through those early papers and provides a historical introduction to the paper in this special issue showing the state of the art in the field and the application of these modern tools to a variety of atmospheric data.