Abstract

The focus of this study was to evaluate emissions of fugitive gases, such as methane and hazardous air pollutants, using scanning open-path Fourier transform infrared spectrometers and open-path tunable diode laser absorption spectroscopy. The study involved a technique, known as radial plume mapping, that uses ground-based optical remote sensing technology. The horizontal radial plume mapping (HRPM) method was used to map surface methane concentrations, and the vertical radial plume mapping (VRPM) method was used to measure emissions fluxes downwind of the site.

HRPM surveys detected the presence of a methane hot spot near the center of the site. Peak concentrations ranged from over 26 parts per minute (ppm) to over 48 ppm above ambient background levels. At the request of the site operator, an additional HRPM survey was conducted while leachate was being pumped from a small holding pond located in the southeast corner of the site to another small holding pond located in the northwest corner of the site. This survey detected an additional methane hot spot located near the northwest corner of the site with concentrations greater than 23 ppm above ambient background levels.

The results of the VRPM surveys found upwind methane flux values between 14 and 20 grams per second (g/s) and downwind methane flux values between 10 and 18 g/s. The downwind methane flux values from 21 and 22 in January 2004 were lower than the corresponding upwind values, probably because the prevailing winds at the time of the surveys carried a large portion of the plume from the upwind hot spot outside of the downwind VRPM configurations.

Contact

Susan Thorneloe

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