SP2 is an ideal instrument for measuring black carbon, known as soot. It is the only probe in the world that directly measures the black carbon in individual aerosol particles. Its high sensitivity and fast response makes it the premier instrument for characterizing pollution sources and measuring black carbon in snow, ice or water.
The instrument measures the time-dependent scattering and incandescence signals produced by individual black carbon containing particles as they travel through a continuous-wave laser beam. Any particle traversing the laser beam will scatter light, and the black carbon component of a particle will absorb some of the laser energy until its temperature is raised to the point at which it incandesces. The amplitude of the incandescence signal is related to the amount of refractory black carbon material contained in the illuminated particle. | 
