A method and apparatus for analyzing, maintaining or adjusting the chemical and physical structure of a CO2 Composite Spray in real-time. A light beam is passed through a portion of the CO2 Composite Spray plume, following which the transmitted light is collected using a detector and analyzed using a computer processing device. Light absorption, reflection and/or florescence data are correlated with CO2 particle density and particle size, spray plume length, organic and inorganic spray additives, and water vapor content. The treatment spray geometry is used to optimize and control a CO2 Composite Spray in precision cleaning, machining, and cooling processes.