Using the 13C/12C carbon isotope ratio to characterise the emission sources of airborne particulate matter: a review of literature.

ABSTRACT

Particulate matter (PM) from atmospheric aerosols contains carbons that are harmful for living organisms and the environment. PM can originate from vehicle emissions, wearing of vehicle components, and dust. Size and composition determine PM transport and penetration depth into the respiratory system. Understanding PM emission characteristics is essential for developing strategies to improve air quality. The number of studies on carbon isotope composition (13C/12C) of PM samples to characterise emission factors has increased. The goal of this review is to integrate and interpret the findings from 13C/12C carbon isotope ratio (δ13C, ‰) analyses for the most common types of emission sources. The review integrates data from 25 studies in 13 countries. The range of δ13C of PM from vehicle emissions was from -28.3 to -24.5 ‰ and for non-vehicle anthropogenic emissions from -27.4 to -23.3 ‰. In contrast, PM ranges for δ13C from biomass burning sources differed markedly. For C3 plants, δ13C ranged from -34.7 to -25.4 ‰ and for C4 plants from -22.2 to -13.0 ‰. The 13C/12C isotope analysis of PM is valuable for understanding the sources of pollutants and distinguishing vehicle emissions from biomass burning. However, additional markers are needed to further distinguish other anthropogenic sources.