Most atmospheric studies have focused on sites located in either rural or urban areas. However, there are regions affected by air from both, such as the city of El Paso. Adjacent to the neighboring city of Juarez, Mexico, and in close proximity to rural areas, the city of El Paso is affected by desert particles and biogenic as well as anthropogenic emissions. Aerosol properties largely depend upon the size of particles; therefore we focus this research on using an inverse reconstruction model, the Environmental Physics Inverse Reconstruction Model, EPIRM, (Roderick Pearson, Rosa M. Fitzgerald and Javier Polanco, 2006) to retrieve particle size distribution using aerosol optical depth data. The optical depth data is obtained from a Multi-filter Rotating Shadow Band Radiometer (MFRSR) installed at the UTEP campus. Our methodology uses Twomey's regularization technique that suppresses ill-posedness by imposing smoothing and non-negativity constraints on the desired size distributions. We have also applied T-matrix codes to study the scattering from irregularly shaped particles that exhibit rotational symmetry. Furthermore, our studies include analysis of the Multiangle Imaging SpectroRadiometer (MISR) aerosol satellite data for the El Paso-Juarez Airshed. We present results of aerosol size distribution for our region using the EPIRM model in conjunction with optical depth data. In addition, we present comparisons of aerosol optical parameters obtained using MISR aerosol satellite information and ground MFRSR radiometer data, for the purpose of improving aerosol characterization. This work will lead to better characterization of aerosols and their impact in our rural-urban interface region. An additional benefit is that it provides a more accurate assessment of regional transport and better boundary conditions for air quality models.