Compound-specific carbon isotope analyses of individual long-chain alkanes and alkanoic acids in Harmattan aerosols

The higher molecular weight n-alkane, n-alkanol and n-alkanoic acid series from higher plant wax are ubiquitous components of aerosol particles in remote areas. The carbon isotopic compositions of individual n-alkanes and n-alkanoic acids have been determined in samples of Harmattan aerosol and composited vegetation wax from Nigeria. The data confirm the terrestrial origin of these compounds and support the distinction among the vegetation sources of C-4 plants (savannah) from C-3 and CAM plants (wet climate, mixed vegetation). The superimposed petroleum components from vehicular emissions in urban areas could not be differentiated from C-3 vegetation by compound-specific isotope analysis. (C) 1997 Elsevier Science Ltd.