SDL has developed a novel Compact Eyesafe Lidar System (CELiS) designed to monitor airborne particulate matter (PM) emissions. It uses a 1.57 µm wavelength commercial laser, an 8 inch off-axis parabolic mirror, and a 200 µm diameter InGaAs avalanche photodetector (APD). The laser, mirror, and APD are mounted on a carbon fiber breadboard and housed in an environmentally-sealed housing. CELiS can operate over an 80°C temperature range with an optical path change of only 100 µm.