احمد محمدی اسلامی

We introduce a software tool for calculating gas concentration in atmosphere from data obtained by employing Differential Optical Absorption Spectroscopy (DOAS) method. By considering the generalized Lambert-Beer’s law and as it is impossible to remove the absorber from light path for determining reference intensity spectrum, applying DOAS method is an appropriate selection. DOAS is being considered as a modern method in the open atmosphere spectroscopy. The final purpose of DOAS method is studying trace gases in open atmosphere, which have differential absorption in ultra-violet and visible spectral region, from long distance. In this technique, one can use light sources including sun, moon and appropriate lamps like xenon lamp. Important features of this method involve measuring several gases and contaminants such as O3, NO2 and SO2 simultaneously, continuity in measurements, high sensitivity in part per billion (ppb) range and determining light path proportional to necessity.