The SootScan™ Model OT21 Transmissometer bench top analyzer has been developed as a simple and robust way of assessing Black Carbon particulate matter (PM) from a variety of sample filters. The analysis can be easily performed in the field or the laboratory, and requires less than thirty seconds to provide optical attenuation and BC mass concentration results. This non-destructive analysis method requires no support gases or consumables. A neutral density photometric standard filter kit is available for verifying instrument calibration and validating the instrument response. The SootScan™ is designed to analyze filters for Black Carbon content which are collected from both ambient and source applications. Importantly, because Black Carbon PM is non-volatile, sample analysis can be performed on archived filters as well as freshly collected ones.