MONITORING OF METHANE IN AMBIENT AIR AS AN INDEX OF STABILIZATION AT LANDFILL SITES = MONITORING OF METHANE IN AMBIENT AIR AS AN INDEX OF STABILIZATION AT LANDFILL SITES

다국어 초록 (Multilingual Abstract)

Methane (CH₄), carbon dioxide (CO₂), and nitrous oxide (N₂O) are well known as being the main landfill gases. We used continuous analyzers to measure CH₄, CO₂ and N₂O in ambient air and also the direction and velocity of the wind at a point near the landfill site to evaluate a simple method of measuring the emission of landfill gases.
When there was a wind velocity over 2-3 m/s blowing from the landfill site to the measurement point, the atmospheric levels of CO₂ ranged from about 380 to 480 ppm, and the N₂O concentrations ranged from about 0.30 to 0.33 ppm, similar to background levels m this urban area. However, the CH₄ concentrations were dependent on the direction and the velocity of the wind. When there was a wind blowing in from the landfill site, CH₄ concentrations were always higher than about 2 ppm, the value considered to be the urban background concentration. It was supposed that gas emitted from the landfill site caused this increase of CH₄ concentration. If the CH₄ concentration increase was approximately equal to zero, we could judge that the landfill gas emission had almost ceased.
The continuous measurement of CH₄ in ambient air near a landfill site is clearly a simple and effective method for monitoring landfill gas emissions and the CH₄ concentration in ambient air may be usable as an index of the degree of stabilization of the landfill site.