Methane mapping in Greater Accra : Isotopic signatures and mobile detection techniques in a developing urban landscape
The study investigated the comprehensive mapping of methane mole fraction in Greater Accra Region, Ghana. It aims to quantify δ13C-CH4, identify sources, and map methane levels, distinguishing between biogenic and thermogenic sources using isotopic analysis. On average, 300 study sites were spotte...
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| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier B.V.
2025
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| Subjects: | |
| Online Access: | http://ir.unimas.my/id/eprint/46971/1/Methane%20mapping%20in%20Greater%20Accra%20-%20Copy.pdf http://ir.unimas.my/id/eprint/46971/ https://www.sciencedirect.com/science/article/pii/S2950357424000362 https://doi.org/10.1016/j.scowo.2024.100036 |
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| Summary: | The study investigated the comprehensive mapping of methane mole fraction in Greater Accra Region, Ghana. It
aims to quantify δ13C-CH4, identify sources, and map methane levels, distinguishing between biogenic and
thermogenic sources using isotopic analysis. On average, 300 study sites were spotted for each district in Greater
Accra Region for methane concentrations mapping. A vehicle equipped with a G2201-i isotopic gas analyser was
employed for isotopic measurements of δ13C-CH4. The number of samples included in the Keeling plot for the
plotting of the regression line in discerning isotopic signatures for the study data ranged from 4 – 19. The
HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory) model was applied to help comprehend the
dispersion patterns and tracing the origins of detected methane mole fraction in specific areas. Miller–Tans
approach was used to estimate the average source signature across the dataset and obtained signature of source
mix (‰) of − 30 ± 1 ‰. The highest methane mole fraction was detected in Tema Metropolis, reaching 5.89 ppm
with δ13C-CH4 value of − 24 ± 2 ‰. The Accra Metropolis also had elevated methane levels at 5.08 ppm with
δ13C-CH4 values of − 24 ± 3 ‰. The isotopic signature of methane mixed-source in Greater Accra, derived using
the Miller-Tans plot (-30 ± 1 ‰), indicating combustion and biomass burning emissions. Generally, the methane
isotopic values in this region suggest a mix of natural gas leaks, wetlands, landfills, biomass burning, combustion
process, and agricultural waste emissions. The data obtained provides a crucial primary representation of
methane emissions in the Greater Accra-Region, and West African environment. |
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