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

Aguilera, Juan, Whigham, Leah D.
Isotopes in environmental and health studies 2018 v.54 no.6 pp. 573-587
C3 plants, C4 plants, aerosols, air quality, anthropogenic activities, biomass, burning, carbon, dust, emissions factor, particulate emissions, particulates, pollutants, respiratory system, stable isotopes
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.