Seasonal changes of sources and volatility of carbonaceous aerosol at urban, coastal and forest sites in Eastern Europe (Lithuania)Masalaite, A., Remeikis, V., Zenker, K., Westra, D., Meijer, H. A. J. & Dusek, U., 15-Mar-2020, In : Atmospheric environment. 225, 11 p., 117374.
Research output: Contribution to journal › Article › Academic › peer-review
We measured stable carbon isotope ratios of total carbon (TC) and organic carbon (OC) in fine carbonaceous aerosol fraction sampled in August and September 2013 at urban, coastal and forest sites in Lithuania. delta C-13 values of TC for all three sites over the whole measurement period varied from -29.3 to -26.6 parts per thousand, which is in the range of particles emitted by fossil fuel combustion in Eastern Europe. The isotopic composition at the forest and coastal site showed a similar variation during two contrasting pollution periods. delta C-13 values in the clean period were more variable, whereas the polluted period was characterized by a gradual enrichment in delta C-13 compared to the clean period. In the polluted period air masses originated from southern, southeastern or southwestern direction, indicating long-range transport of pollutants from Eastern Europe and Southern Europe to Lithuania. Oxidative processing during long-range transport or the different source signatures (e.g., enriched C-13 signature of gasoline used in Western Europe vs. Eastern Europe) could cause the less negative delta C-13(OC) values during the polluted episode. delta C-13 for OC desorbed from the filter samples was separately measured during three different temperature steps (200 degrees C, 350 degrees C and 650 degrees C). OC desorbed at 200 degrees C had the most depleted C-13 signature of around -29 parts per thousand at all three sites.
A comparison with previously published data measured during the winter at the same sites showed that both TC and OC had less negative delta C-13 values in winter than in summer, which can be explained by the contribution of biomass/coal burning sources in winter. At the urban site delta C-13 of OC did not change much with increasing desorption temperature in winter, which is typical for primary sources, but in the summer delta C-13 of OC was depleted for lower desorption temperatures, possibly due to the influence of SOA formation. A higher fraction of more refractory OC in summer compared to winter-time suggests active photochemical processing of the primary organic aerosol as an important process at all three sites.
|Number of pages||11|
|Publication status||Published - 15-Mar-2020|
- Aerosol, Isotopic composition, IRMS, SECONDARY ORGANIC AEROSOL, STABLE CARBON, ISOTOPIC COMPOSITIONS, ATMOSPHERIC AEROSOLS, SOURCE APPORTIONMENT, DICARBOXYLIC-ACIDS, CHEMICAL-CHARACTERIZATION, PARTICULATE MATTER, BACKGROUND SITES, FOSSIL SOURCES