Air quality and visibility in the Green River Basin in Southwest Wyoming has deteriorated in recent years, a period that has witnessed an explosive growth in natural gas well development, notably in the Jonah and Pinedale Anticline fields. The Southwest Wyoming Visibility Study (SWYVIS), carried out in February and March 1996, characterized the air quality of the Upper Green River Basin through the use of the Wyoming KingAir research aircraft. In addition to meteorological observations, flight measurements focused on boundary layer aerosol and trace gas concentrations. Observations of light scattering by the particles, and analyses of averaged particulate composition, were also carried out. The measurements include particle number densities, black carbon (BC) mass loadings, SO₂, CH₄ and other VOC mixing ratios up to 6000 cm^-3, 550 ng m^-3, 50 ppb, 2.78 ppm, and 80 ppb, respectively. The spatial variability of the pollutant concentrations have been mapped along the flight tracks, thereby providing a comprehensive overview of both unpolluted and locally impacted air quality in the region during late winter, prior to extensive natural gas well development.

Air quality modeling studies are being conducted using Penn State's Mesoscale Model, MM5, coupled with the Community Multiscale Air Quality (CMAQ) and Sparse Matrix Operator Kernel Emissions (SMOKE) models. Model outputs are being interpolated and compared with the flight tracks. Locations of point and non-point sources are also being determined through the use of backward trajectories. The air quality modeling, in association with the airborne measurements and other nearby air quality studies conducted at approximately the same time as SWYVIS, will allow an air quality baseline for the region to be determined.