A method and apparatus are described for monitoring an area or areas for the presence of gaseous materials, particularly pollutants, by collecting and analyzing infrared radiation present in the selected area, wherein the apparatus contains a computer controlled platform which positions a reflective surface in azimuth and elevation to direct said radiation into an interferometer for analysis. The results of the spectrometric analyses are made available in a form understandable to the person or device monitoring the area for the presence of specified materials. The results of the spectrometric analysis may, for example, be displayed on a video unit, printed or used to sound an alarm.