A multi-stage differential mobility analyzer (MDMA) for aerosol
measurements includes a first electrode or grid including at least one
inlet or injection slit for receiving an aerosol including charged
particles for analysis. A second electrode or grid is spaced apart from
the first electrode. The second electrode has at least one sampling
outlet disposed at a plurality different distances along its length. A
volume between the first and the second electrode or grid between the
inlet or injection slit and a distal one of the plurality of sampling
outlets forms a classifying region, the first and second electrodes for
charging to suitable potentials to create an electric field within the
classifying region. At least one inlet or injection slit in the second
electrode receives a sheath gas flow into an upstream end of the
classifying region, wherein each sampling outlet functions as an
independent DMA stage and classifies different size ranges of charged
particles based on electric mobility simultaneously.