A process for determining a location and size of a gas source within an area with a spectrometer gas monitor includes: providing the spectrometer gas monitor; performing fence line monitoring of the area with the spectrometer gas monitor; collecting spectroscopic data over multiple open paths around the area with the spectrometer gas monitor; measuring atmospheric conditions along gas inflows and gas outflows of the area; subtracting a background for a selected gas from the spectroscopic data; applying a boundary constraint to the spectroscopic data; determining an atmospheric concentration of air entering the area; applying bootstrapping to the spectroscopic data; applying zero minimum elimination to the spectroscopic data; and producing inversion data from the spectroscopic data to determine the location and size of the gas source within the area.