Laser and Optical Techniques Employed in Enviromental Monitoring

Sammanfattning: Monl torlng of trace gases in the atmosphere has been performed wl th differential absorption lldar and differential optical absorption spectroscopy. A new mobile differential absorption lldar system has been constructed. It is described in detail and examples of 502 and N02 measurements are given. Studies of the N02 concentration distribution in an urban area during a temperature inversion were performed. ~tection of c12 with DIAL was invest !gated. Using a narrow-bandwidth laser system range-resolved measurements of NO and Hg were investigated. Mapping of NO and Hg plumes was performed. The use of mercury as a tracer gas for geothermal energy exploration was investigated during a field test in Iceland. Contrary to expectations very low mercury concentrations were detected. A high-resolution differential optical absorption spectroscopy system has been constructed and applied in long-path moni torlng of 502 and N02. Detection of atmospheric atomic mercury was investigated. A multipass absorption cell (White cell) has been constructed and used for spectroscopic measurements. Weak oxygen absorption lines in the vicinity of the Hg line were studied both with laser and optical techniques.