Assessing Diurnal Variations in Methane Emissions from Landfills and Impact on Whole Landfill Emissions Estimates

Investigators: University of Delaware; Yolo County, CA; University of Southampton

Start Date:
January 2022

Award Amount:

Whole landfill methane emission measurements obtained by interrogating the plume of methane above and/or downwind of a landfill are the gold standard for assessing landfill emissions. However, these surveys are almost always limited to times of the day when the wind is moderate to strong and the atmosphere is well-mixed. For example, a recent study of California’s methane point sources, including landfills and composting facilities, was based on airborne data collected between 10-15 PST (Duren et al., 2019). Because moderate to strong winds increase atmospheric soil mixing, and consequently increase diffusion and dispersion gradients out of the landfill, measurements made under windy conditions at particular times of the day may be higher than the average, overestimating daily emissions by up to 70% (see data herein). Thus, landfills may emit much less methane than reported from whole-landfill data.

Project objectives are:

• Assess the significance of diurnal methane emission variations for different landfill covers and landfill operations

• Quantify the measurement bias of whole landfill methane emission measurements using currently employed technologies

• Investigate the influence of gas collection on diurnal emission variations