Intercomparison of Methane Emission Rate Methods Using Aerial and Ground-Level Mobile Monitoring at New York State Landfills

High Resolution Image Download MS PowerPoint Slide Methane concentrations were measured at major New York State (NYS) landfills in 2021 and 2022 using both aerial and ground-level monitoring from a mobile research lab (MRL) to determine facility emission rates. These emission rates were estimated by a mass balance method using Gauss’s Theorem and a Gaussian Plume Dispersion (GPD) method. Three separate emission rates were calculated for each of the facilities when data was available, two of which were calculated using both the GPD and mass balance methods from the MRL data, and the third using the more rigorous aircraft data and mass balance method, which was used as the reference estimate. Both MRL GPD and mass balance methods come with considerable uncertainty, which is mainly driven by stability class and distance for the GPD and plume height for the mass balance. All but one of the GPD estimates fell within the uncertainty range of the aircraft estimates and estimated a CH 4 emission rate range of 262–3896 kg h –1 . The MRL mass balance estimates, however, proved to be quite different from the aircraft aside from one case with an estimated range of 463–6285 kg h –1 . The poor agreement between the MRL mass balance and the aircraft reduces confidence in these estimates. The observations were also compared to the 2021 and 2022 self-reported EPA Greenhouse Gas Reporting Program (GHGRP) Inventory. The aircraft estimates were, on average, 2.2× greater than the GHGRP while the MRL estimates were more variable in comparison with the inventory. This study provides information on these different estimation methods and will help improve and inform the GHG emissions inventory.