Methane is a powerful greenhouse gas released from sources like natural gas systems, landfills, farms, and wetlands. To reduce emissions effectively, we need to know where the methane comes from. This study used the ratio of ethane to methane to tell apart emissions from natural gas and biological sources. Using aircraft and mobile measurements in urban and oil/gas regions, we found that natural gas sources had higher ethane levels. This method helps identify methane sources in different areas, improving emission estimates and supporting more targeted climate policies and mitigation strategies.