An overview of our laser remote sensing effort is presented. Using both fundamental and frequency-doubled CO 2 laser radiation in a differential absorption LIDAR (DIAL) system, background concentrations of CO, NO, and C 2 H 4 in the atmosphere as well as increases due to localized emission sources have been measured. These species have been detected using the backscattered laser radiation from topographic targets at ranges to 2.7 km with a sensitivity of ± 10 ppb. In addition, using a dual-laser DIAL system, the effect of induced correlation of the LIDAR returns due to atmospheric turbulence has been investigated. These results have been used to help quantify the accuracy of the DIAL measurements and are shown to be consistent with theory.