MEXA-1370 PM - Super-Low-Mass Particulate Matter Analyzer

Samples of tunnel-diluted exhaust gas are drawn through a quartz filter according to conventional procedures. Then: Filter is placed in the analyzer' s furnace and heated to 980° C in a N2 gas flow. SOF and sulfate in trapped particles are vaporized by heat in N2 atmosphere. Vaporized sulfate is deoxidized to SO2 by heat and measured by SO2 NDIR detector. Vaporized organic fraction is oxidized by constant flow of O2 and measured as CO2 by NDIR detector. Output of CO2 detector is integrated while N2 is flowing to determine SOF mass. Output of CO2 detector is integrated while O2 is flowing to determine soot mass. Detection of masses as low as 0.2 µ g is possible in only four minutes using this method. Application: Precision measurements of super-low particulate levels. SOF, soot, and sulfate masses in diesel particulate emissions. Efficiency of exhaust after-treatments for reducing PM.