Direct Quantification of PM2.5 Fossil and Biomass Carbon within the

Environ. Sci. Technol. 1999, 33, 4146-4154

Direct Quantification of PM2.5 Fossil and Biomass Carbon within the Northern Front Range Air Quality Study’s Domain DONNA B. KLINEDINST* AND LLOYD A. CURRIE National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8372

Radiocarbon (14C) analyses of PM2.5 (particulate matter with an aerodynamic diameter of 2.5 µm or less) of both ambient and source samples from the Northern Front Range Air Quality Study (NFRAQS) in Colorado were performed. The 14C analyses were undertaken to provide direct fossil vs modern (biomass) carbon source discrimination data for a subset of summer and winter 1996-1997 samples collected within the Denver metropolitan area. Samples were prepared for 14C accelerator mass spectrometry measurements using techniques specially developed for small samples, i.e.,