ESRIG-EES colloquium: Norbertas Kairys, Eirini Sarli and Tarun Rohra, MSc EES students
| When: | Tu 21-01-2020 15:30 - 17:00 |
| Where: | 5159.0114, Nijenborgh 6 (Energy Academy) |
Speaker | Norbertas Kairys, MSc EES student.
Title | Delta13C signature of different aerosol sources around the World.
Summary | Since the 1980s, carbon isotopes have been applied in studies of air pollution to characterize emissions from fossil fuels and biomass burning. Nonetheless, there are still many aspects of carbon isotope ratios from fuel oxidation that are unknown. Distinguishing fossil fuel and biomass burning sources is necessary to develop effective strategies for more efficient control of aerosol particle pollution in order to improve air quality and combat global warming. Carbon has three naturally occurring isotopic forms, two of which are stable ( 12 C and 13 C) and one of which is radioactive ( 14C). Because of their differences in atomic mass, some biological reactions favour the uptake of one versus the other isotope . Therefore, aerosols from different fuel sources will differ in isotope ratio and in this case we are particularly interested in stable isotope ratio ( 12 C/ 13 C) also known as 13 C isotopic signature. Since carbonaceous aerosols are of the main focus in this project, the total carbon (TC) is further divided in organic carbon (OC) and elemental carbon (EC) which gives more precise information where the aerosols are originating from. This project focus on 13 C signature of different aerosol samples from Lithuania, Italy and China. The main objective is to determine the different aerosol sources 13 C content as accurate as possible and compare the values with previous literature findings. In this study samples of burning various biomass are measured and compared to coal burning samples. In addition samples of aerosol particles emitted from cruise ship, from passenger vehicles and even from food cooking are measured and compared.
Speaker | Eirini Sarli, MSc EES student.
Title | Black carbon sources in lake sediments.
Summary | Air Pollution by aerosols is one of the current major problems that China is facing. Black carbon (BC) particles are emitted by combustion fossil fuels and vegetation into the atmosphere and could cause problems in health, respiration, everyday life as well as contributing to global warming, as in a form of soot absorbs sunlight and warms the Earth. Sudden increase in concentrations of black carbon has occurred since 1950’s (Han et al., 2016) and it is essential to know and reduce these emissions. Several studies have examined the air samples and what their source contribution to BC is. However, in this way, it is only possible to test the current sources. Instead of that, by drilling sediment cores and isolating BC, which was deposited from the air on lake surfaces, it is also possible to observe the BC sources of the past. The main goal this thesis is to develop an optimal extraction method of BC via combustion and the source apportionment of BC from a sediment core through radiocarbon analysis. For this research project, a Chinese lake sediment core originating from Lake Huguangyan Maar located in the South-Eastern part of China is examined. Subsequently, from the source apportionment, we observe that there is a substantial non-fossil contribution pattern below 1950’s, and only after 1960’s and 1980’s a more fossil footprint is appeared as a matter of the industrialization, with the latest years until 2018 to be mainly focused on non-fossil contributions.
Speaker | Tarun Rohra, MSc EES student.
Title | Solar Storms, Supernovae or Neither?
Summary | Investigating the radiocarbon increase around 400 BCE Abstract Radiocarbon is a cosmogenic isotope generated in the upper atmosphere and reflects changes in the cosmic flux due to geomagnetic, solar and stellar activity. However, by Carbon Cycle processes such as oceanic outgassing, volcanic eruptions and fossil fuel burning, all of which tend to dilute the concentration of Radiocarbon in the atmosphere by the addition of stable isotopes of carbon. Nonetheless, prior to the Nuclear Age, there was no terrestrial process which could result in a sudden increase of Radiocarbon production. Within the last decade, it has been shown that sudden and dramatic increases in radiocarbon production can occur. The evidence comes from known-age tree-ring archives, where growth incorporates much more 14C than the year before. The consensus now is that solar super flares are responsible for these sudden and significant increases in 14C production. These pose a serious threat to satellite telecommunications and global infrastructure, so understanding their magnitude and occurrence frequency is a matter of urgency. Provisional data suggests an anomalous increase in 14C production may have occurred around 400 BCE. This study looks at annual radiocarbon records from the period 414 – 394 BCE and analyses and interprets for any evidence of unusual or extreme solar behaviour.