Comparison of Landfill Methane Emission Quantification Using Multiple Observation Methods.

Area of Science:

• Environmental Science
• Atmospheric Chemistry
• Remote Sensing

Background:

• Landfills are major sources of anthropogenic methane (CH4) emissions in Canada.
• Accurate quantification of CH4 emissions is vital for climate change mitigation and validating emission inventories.
• Variability in landfill emissions and site topography present significant quantification challenges.

Purpose of the Study:

• To compare the effectiveness of seven different methane emissions quantification strategies and platforms at a Canadian landfill.
• To assess the suitability of various remote sensing and in situ methods for quantifying landfill CH4 emissions across different detection limits.
• To determine which methods are most effective for covering the majority of Canadian landfill sites.

Main Methods:

• Comparison of ground-based, aircraft-based, and satellite-based remote sensing techniques.
• Inclusion of ground-based stationary, mobile, and aircraft-based in situ observation strategies.
• Utilized a 3.5-year monitoring period, including a 28-month deployment of a low-precision sensor network.

Main Results:

• All methodologies quantified a wide range of methane emissions rates (approximately 200-2000 kg·h⁻¹).
• Average estimated emissions rates agreed within the associated uncertainties across different methods.
• Remote sensing methods have higher detection limits, suitable for 20-50% of Canadian landfills, while ground-based in situ methods are suitable for most accessible sites.

Conclusions:

• Ground-based in situ methods offer superior detection limits for quantifying methane emissions from the majority of accessible Canadian landfills.
• Remote sensing techniques are valuable but limited in their ability to detect lower emissions rates from a substantial portion of landfill sites.
• A combination of methods may be necessary for comprehensive methane emissions monitoring from diverse landfill types.