Landfill Methane Emissions Tracked by Airborne Sensors

A recent study has revealed that work faces in U.S. landfills are responsible for the majority of methane emissions. The findings, published in the journal Environmental Science and Technology, come from a team of researchers from Carbon Mapper, a nonprofit in California focused on reducing greenhouse gas emissions, along with scientists from Arizona State University and the U.S. Environmental Protection Agency.

While carbon dioxide is the main driver of climate change due to its high volume, methane is much more effective at trapping heat, even though it has received less attention because of its lower total emissions. However, growing concern has emerged over methane, especially as more sources have been identified in recent years.

In this study, the researchers concentrated on methane emissions from landfills, which primarily occur as plant-based materials, like food waste, decompose. To gather data, the team used planes equipped with air-quality sensors to fly over 217 landfills in 17 states. They discovered measurable methane levels at half of the landfills surveyed.

The team identified an unexpected source: the largest portion of methane emissions was coming from the work faces, the areas where fresh waste is added. Very little methane was found in other parts of the landfills.

The study also found that many landfills equipped with gas-capturing technology were still releasing substantial amounts of methane. The researchers suggest that this is because these landfills are often the largest, and as a result, they emit the most methane, despite efforts to capture the gas. Interestingly, a significant number of landfills were not releasing any detectable amounts of methane.

This research highlights the importance of addressing emissions from the work faces of landfills and improving gas capture technologies to better manage methane and reduce its environmental impact.