Quantifying Fossil Fuel CO2 Component over Dakar from 1960 to 2010 by Radiocarbon Observation in Atmospheric CO2 and Using Mauna Loa as Background
Matar Sène,
Maurice Ndeye
Issue:
Volume 4, Issue 4, July 2019
Pages:
52-60
Received:
2 July 2019
Accepted:
26 July 2019
Published:
3 September 2019
Abstract: We investigated the atmospheric ∆14C level and the fossil fuel CO2 concentration in Dakar area from 1960 to 2010 by using the radiocarbon measurements obtained from tree leaves samples. We used the Carbon-14 dating method with a Liquid Scintillation Counter and an Accelerator Mass Spectrometer. The samples were subjected to physical and chemical pretreatments, then, they were transformed into benzene for the counting. The results show that the largest maxima of the 14C concentration (∆14C) are recorded at sites such as the SAR Factory (773‰ in 1964), Mbao Forest 2 (677‰ in 1966) and UCAD Botanic Garden (522‰ in 1970) and the smallest minima are the Airport Runway (45‰ in 2010), the Beach 2 (48‰ in 2009), the Mbao Forest 2 (59‰ in 2007), the SAR Factory (71‰ in 2005), Soumbedioune Market (80‰ in 2003) and Ucad Botanic Garden (91‰ in 2000). The Comparative curve of the minimum and the maximum values of ∆14Cbg (background) and ∆14Cmeas (measured) show that 14C concentration of the sites are lower than 14C concentration in clean air. This can be correlated with the increase of the fossil fuel derived CO2 caused by human activities such as population density, industrials emissions, and traffic. The evaluation of the fossil fuel concentration (CO2ff) by mass balance equations, show, in most of the sites, an increase of the level of CO2ff. Exceptional cases are obtained in Mbao Forest 1 and for UCAD Botanic Garden sites. One explanation of the values is that sites are much wooded these last years.
Abstract: We investigated the atmospheric ∆14C level and the fossil fuel CO2 concentration in Dakar area from 1960 to 2010 by using the radiocarbon measurements obtained from tree leaves samples. We used the Carbon-14 dating method with a Liquid Scintillation Counter and an Accelerator Mass Spectrometer. The samples were subjected to physical and chemical pr...
Show More
