The Time-of-Flight Aerosol Chemical Speciation Monitor mass spectrometer allows to achieve real time chemical characterization of the main organic and inorganic components (i.e., sulphate, ammonium, nitrate, chloride) of the non-refractory sub-micrometric atmospheric particulate.

Principle of operation: the aerosol enters in the inlet where the aerodynamic lens efficiently samples and focuses the sub-micron particles to the next vacuum chamber; here, the particles impact a porous tungsten surface resistively heated to approximately 600°C which vaporizes the non-refractory particulate; the vaporized matter is subsequently ionized by electron impact and detected by the TOF analyser. Furthermore, one of the most important features of this technology is that it is not subject to sampling artifacts that affect the collection of semi-volatile particulate components on filters.