Odor impact zones around landfills: Delineation based on atmospheric conditions and land use characteristics.

Odors emitted from landfills can result in complaints by the residents living near the landfills. The aim of this study was to develop an assessment and delineation tool to identify the areas which can be impacted by the odors released from landfills based on land use characteristics and atmospheric conditions; and estimate the number of people who may be impacted. Odor emissions and dispersion analyses were conducted for three case study landfills under different atmospheric conditions in view of the land use characteristics around each landfill. Odor emissions and odor intensity levels were estimated based on the total gas production and the level of odorous compounds present in the landfill gas using the Landfill Gas Emissions Model (LandGEM) software. To delineate the odor impact zones, air dispersion characteristics of the odorous gases were analyzed using the dispersion modeling software, Areal Locations of Hazardous Atmospheres (ALOHA), and mapped using ArcGIS. Impact zone analyses were conducted based on the odor perception thresholds. The methodology developed involved coupling landfill gas emissions model (LandGEM), dispersions model (ALOHA) and mapping software for land use and population density (ArcGIS) allows visualization of the potential impact zones for preliminary delineation of the buffer zones around landfills, developing appropriate mitigation measures in view of the changing land use characteristics and population density around the existing and planned landfills. The odor impact zone delineation methodology was named Land-OZ (short for Landfill Odor Impact Zone). Results of using the odor impact zone tool showed that atmospheric stability could increase the odor impact radius around the three landfills evaluated between 340 and 1100 percent depending on the land use characteristics of the surrounding areas.