A Novel Ground Based Mass-Balance Method for Methane Emission Quantification

Emission of CH4 from landfills in Canada are not well constrained and in Ontario constitute the largest point source emitters. The purpose of this study was to develop and test a ground based method for quantifying CH4 emissions from large sources. Emissions of CH4 were quantified from the Keele Valley Landfill (KVL) using ground based mobile mass balance approach where a mobile cavity ring down spectroscopy (CRDS) instrument captured the downwind field of CH4 mixing ratio enhancements relative to the background. The approach involves measuring the downwind field of enhancements at successively further distances from the source until the integrated CH4 enhancements converge. On multiple days in April and May 2016 multiple transects were driven upwind and at increasing distances downwind from the KVL with the CRDS in a vehicle in order to determine integral flux emission estimates. The KVL was found to be a major local source of CH4 even though CH4 collection used for electricity generation is now terminated. An average emission rate of 429 199 kg/hr of CH4 was measured in 2017 on several days, which is less than the ECCC emission inventory value of 2149 kg/hr [2015]. The source of the discrepancy is not fully understood, but may be related to the shutdown of the KVL facility. The largest source of uncertainty in our emission estimate calculation was the height of the PBL, which