AERMOD has recently become the preferred air dispersion model for near-field regulatory applications in EPA's "Guideline on Air Quality Models," replacing the ISCST3 air dispersion model. Urban and complex terrain influences on the structure of the planetary boundary layer present numerous challenges to adequately characterizing dispersion of air contaminants in these environments. The concentration and diversity of emission sources within the urban environment further complicates this challenge, while at the same time contributing to its importance. AERMOD currently parameterizes the enhanced turbulence due to the nocturnal urban heat island based on a user-specified population. Enhancements to mechanical turbulence due to urban roughness elements are not explicitly accounted for in the current AERMOD formulations. A number of AERMOD implementation issues have been identified in relation to these characteristics of the AERMOD model urban formulation. This poster will present plans for enhancing the AERMOD model for urban applications by utilizing additional data sources for land cover from the National Land Cover Data (NLCD) for 2001, coupled with estimates of average obstacle heights derived from National Elevation Dataset (NED) and Shuttle Radar Topography Mission (SRTM) data. Combining these data sources will allow for a more complete characterization of land cover in terms of both thermal and mechanical influences of the surface on the atmospheric boundary layer. These enhancements to AERMOD will also be designed with the goal of accommodating the use of additional data resources, such as those envisioned for the National Urban Database and Access Portal Tool (NUDAPT), to better inform the model. The impact of these enhancements on other aspects of the AERMOD formulation will also be addressed.