The influence of atmospheric pressure on landfill methane emissions.

Abstract Landfills are the largest source of anthropogenic methane (CH 4 ) emissions to the atmosphere in the United States. However, few measurements of whole landfill CH 4 emissions have been reported. Here, we present the results of a multi-season study of whole landfill CH 4 emissions using atmospheric tracer methods at the Nashua, New Hampshire Municipal landfill in the northeastern United States. The measurement data include 12 individual emission tests, each test consisting of 5–8 plume measurements. Measured emissions were negatively correlated with surface atmospheric pressure and ranged from 7.3 to 26.5 m 3 CH 4 min −1 . A simple regression model of our results was used to calculate an annual emission rate of 8.4×10 6 m 3 CH 4 year −1 . These data, along with CH 4 oxidation estimates based on emitted landfill gas isotopic characteristics and gas collection data, were used to estimate annual CH 4 generation at this landfill. A reported gas collection rate of 7.1×10 6 m 3 CH 4 year −1 and an estimated annual rate of CH 4 oxidation by cover soils of 1.2×10 6 m 3 CH 4 year −1 resulted in a calculated annual CH 4 generation rate of 16.7×10 6 m 3 CH 4 year −1 . These results underscore the necessity of understanding a landfill's dynamic environment before assessing long-term emissions potential.