The Sources of Aerosol Elemental Carbon at Allegheny Mountain

-Aerosol elemental carbon measurements were taken at two rural sites in southwestern Pennsylvania during August 1983. Carbon, though a small part of the aerosol mass at both sites, was a leading constituent of the aerosol on an atom basis. Time-weighted average concentrations at Allegheny Mountain and Laurel Hill were 1.2 and 1.4 #g m-3, respectively. Absolute Principal Component Analysis followed by multiple regression and Chemical Mass Balance techniques were utilized to apportion the measured elemental carbon to its sources. Motor vehicles were estimated to be the largest source of elemental carbon at the two sites, contributing 41-68% and 34-56% at Allegheny Mountain and Laurel Hill, respectively. Key word index: Atmospheric aerosol, elemental carbon, lead, source apportionment, chemical mass balance, principal component analysis.