A system and method for quantifying an emission source is provided. The system and method obtain a plurality of emission concentration measurements at one or more sampling points and wind data over the time the emission concentrations are measured. For each sampling point, a virtual sampling arc can be constructed using the emission concentration measurements taken at the sampling point, the wind data for when the emission concentration measurement were taken and an approximate distance to the emission source. The virtual sampling arcs can then be used to construct one or more virtual sampling grids and the amount of emissions emanating from the emissions source approximated from the virtual sampling grids.