Knowledge Bank

The spectral characteristics of gaseous pollutants offer an attractive method of determining their concentrations in the atmosphere. These concentrations need to be determined under two circumstances: over path lengths on the order of a kilometer or so where the pollutants are at ambient temperature and low concentrations (~0.1 ppm), and at the exit of smoke stacks where the pollutants are at temperatures as high as $600\circ$ F and high concentrations (~100 ppm). For long path measurements absorption spectroscopy techniques appear most suitable. For smoke plume measurements the techniques of emission spectroscopy and scattering from laser beams are being studied. This paper will discuss the various programs funded by the Air Pollution Control Office which are related to the above problems. In addition, some data recently obtained during a field measurements program in the Los Angeles area will be presented.