Aerosol source (biomass, traffic and coal emission) apportionment in Lithuania using stable carbon and radiocarbon analysis

In the present study, a combination of the stable carbon isotope ratio (C-13/C-12) with radiocarbon data (C-14) allowed us to perform the aerosol source apportionment. Filter samples of PM1 were collected during the warm and cold periods in rural and urban sites in Lithuania. The C-14/C-12 ratio of total carbon (TC) was measured using the single stage accelerator mass spectrometer quantifying of fossil and non-fossil derived aerosol emissions. The C-13 value was measured using an elemental analyser interfaced with an isotope ratio mass spectrometer. We have found that the highest fraction of contemporary carbon (f(c)=0.82) was measured during a warm period in a rural location. A higher fraction of fossil fuel-derived carbon was observed for air masses transported from highly industrialized Western European regions during both seasons. Isotope mass balance calculations revealed that the traffic emissions composed 15 and 25% in rural and urban sites, respectively, and did not change during either season. Input from coal-derived aerosol particles was estimated to be 15% at an urban site during the cold period. The combination of the stable carbon isotope ratio with the radiocarbon data allowed us to distinguish coal, liquid fossil fuel combustion, and non-fossil derived aerosol particle emissions.