Atmospheric carbon: The importance of accelerator mass spectrometry

Abstract

Knowledge of the sources, transport and sinks for carbonaceous gases and particles in the atmosphere is of great concern both for understanding the carbon cycle and for assessing man's influence on atmospheric visibility, health effects and climate. Carbon isotopes (notably 14C) are quite important in tracing such species and in validating models based on emissions inventories, dispersion algorithms, and trace inorganic or organic mass balance. Accelerator mass spectrometry (AMS) offers considerable promise to this field, for useful sample size may be decreased by three orders of magnitude, resulting in greatly improved spatial, temporal and chemical resolution. Special problems which have been addressed with the use of 14C-AMS are reviewed, including the study of sources of elemental, organic (paniculate), and gaseous carbon compounds in the atmosphere. This report concludes with a brief review of techniques which have been used for 10–100 μg carbon samples, and a discussion of special atmospheric (urban particulate) Standard Reference Materials.