Patent ID: 7213476

Claim:
A multi-stage differential mobility analyzer (MDMA) for aerosol measurements, comprising: a first electrode or grid including at least one inlet or injection slit for receiving an aerosol, said aerosol including a plurality of charged particles for analysis; a second electrode or grid spaced apart from said first electrode, said second electrode having at least one sampling outlet disposed at a plurality different distances along its length, a volume between said first and second electrode or grid between said inlet or injection slit and a distal one of said plurality of sampling outlets forming a classifying region, said first and second electrodes for charging to suitable potentials to create an electric field within said classifying region, and at least one inlet or injection slit in said second electrode for receiving a sheath gas flow into an upstream end of said classifying region; wherein each said sampling outlets at each of said plurality of distances function as independent DMA stages and classify different size ranges of said charged particles based on electric mobility simultaneously.