We determined the atmospheric dinitrogen monoxide (N₂O) concentration in an open type domestic waste landfill site and a closed system type domestic waste landfill site by continuously using an extractive N₂O analyzer with infrared absorption (infrared N₂O analyzer) and a non-extractive open-path type N₂O analyzer, with infrared absorption (open-path N₂O analyzer), and investigated the increase of nitrous oxide concentration caused by landfill gas.
When the wind was blowing at over 1-2 m/s, the N₂O concentrations ranged from about 0.30 to 0.33 ppm, and they were similar to ordinary concentrations in the urban area. However, when it was blowing at less than 1 m/s or was calm continuously, N₂O emitted from the landfill site could increase the atmospheric N₂O concentrations.
The open-path type N₂O analyzer could show a rough change of N₂O concentration in a small-scale landfill site. Moreover, the N₂O generating speed per unit reclamation area in the landfill site, where residue of crushed incombustible and large size wastes were landfilled, was estimated to be about 60μg/m²·h from the measured increase rate of N₂O concentration.