Isotope signatures of methane sources in Asia

The present data set is a set of stable carbon isotope signatures of various methane sources in Asia (Japan, Thailand and Bangladesh). The stable carbon isotope signatures were estimated from a set of air samples collected in proximity to individual sources including landfills, wastewater treatment facilities, rice paddies and agricultural combustion. The data set also include ethane to methane enhancement ratios for fossil fuel and combustion sources. For each air sample collected in a glass flask, methane and ethane concentrations were measured by a mid-infrared absorption spectrometer MIRA Pico analyzer on site. The air samples were analyzed for stable carbon isotope ratio of methane by a method described by Umezawa et al. (2020). Isotope signature and ethane to methane enhancement ratio for each source were calculated from a set of air samples under influence of a single source. The methodologies are detailed in Umezawa et al. (2026).