Assessment of invasive muskrat Ondatra zibethicus distribution and impacts on ecosystems in Lithuania

Butautytė-Skyrienė, G., Paulauskas, A., Ulevičius, A

Sources and atmospheric processing of size segregated aerosol particles revealed by stable carbon isotope ratios and chemical speciation

Size-segregated aerosol particles were collected during winter sampling campaigns at a coastal (55°37′ N, 21°03′E) and an urban (54°64′ N, 25°18′ E) site. Organic compounds were thermally desorbed from the samples at different temperature steps ranging from 100 °C to 350 °C. The organic matter (OM) desorbed at each temperature step is analysed for stable carbon isotopes using an isotope ratio mass spectrometer (IRMS) and for individual organic compounds using a Proton Transfer Reaction Time-of-Flight Mass Spectrometer (PTR-MS). The OM desorbed at temperatures <200 °C was classified as less refractory carbon and the OM desorbed at temperatures between 200 °C and 350 °C was classified as more refractory carbon. At the coastal site, we identified two distinct time periods. The first period was more frequently influenced by marine air masses than the second time period, which was characterized by Easterly wind directions and continental air masses. During the first period OM contained a large fraction of hydrocarbons and had a carbon isotopic signature typical of liquid fossil fuels in the region. Organic mass spectra provide strong evidence that shipping emissions are a significant source of OM at this coastal site. The isotopic and chemical composition of OM during the second period at the coastal site was similar to the composition at the urban site. There was a clear distinction in source contribution between the less refractory OM and the more refractory OM at these sites. According to the source apportionment method used in this study, we were able to identify fossil fuel burning as predominant source of the less refractory OM in the smallest particles (D50 < 0.18 μm), and biomass burning as predominant source of the more refractory OM in the larger size range (0.32 < D50 < 1 μm). Chemical and isotopic analysis of carbonaceous aerosol particles revealed a clear distinction in source contribution at coastal and urban sites

Sources and atmospheric processing of size segregated aerosol particles revealed by stable carbon isotope ratios and chemical speciation

Size-segregated aerosol particles were collected during winter sampling campaigns at a coastal (55°37′ N, 21°03′E) and an urban (54°64′ N, 25°18′ E) site. Organic compounds were thermally desorbed from the samples at different temperature steps ranging from 100 °C to 350 °C. The organic matter (OM) desorbed at each temperature step is analysed for stable carbon isotopes using an isotope ratio mass spectrometer (IRMS) and for individual organic compounds using a Proton Transfer Reaction Time-of-Flight Mass Spectrometer (PTR-MS). The OM desorbed at temperatures <200 °C was classified as less refractory carbon and the OM desorbed at temperatures between 200 °C and 350 °C was classified as more refractory carbon. At the coastal site, we identified two distinct time periods. The first period was more frequently influenced by marine air masses than the second time period, which was characterized by Easterly wind directions and continental air masses. During the first period OM contained a large fraction of hydrocarbons and had a carbon isotopic signature typical of liquid fossil fuels in the region. Organic mass spectra provide strong evidence that shipping emissions are a significant source of OM at this coastal site. The isotopic and chemical composition of OM during the second period at the coastal site was similar to the composition at the urban site. There was a clear distinction in source contribution between the less refractory OM and the more refractory OM at these sites. According to the source apportionment method used in this study, we were able to identify fossil fuel burning as predominant source of the less refractory OM in the smallest particles (D50 < 0.18 μm), and biomass burning as predominant source of the more refractory OM in the larger size range (0.32 < D50 < 1 μm). Chemical and isotopic analysis of carbonaceous aerosol particles revealed a clear distinction in source contribution at coastal and urban sites

Nocturnal aerosol particle formation in the North China Plain

New particle formation is one of the major sources of atmospheric aerosol particles. Beside daytime nucleation, nocturnal new particle formation was also found in different regions around the world. Compared with daytime nucleation events, the understanding of nocturnal ones is still sparse. The variety of aerosol particle physico-chemical properties, including particle number size distribution, volatility and hygroscopicity were measured in the North China Plain during July-August 2013. During the observation period, rapid increase in ultrafine particle number concentration was attributed to new particle formation. The nocturnal new particle formation rate was 45 cm(-3)s(-1), which is 1.25 times higher than an observed daytime value. Condensation sink was found to be 0.055 s(-1)

Seasonal observation and source apportionment of carbonaceous aerosol from forested rural site (Lithuania)

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